AMNA NAWAZ: In addition to shortages of weapons and artillery in its war with Russia, Ukraine faces a critical manpower problem.

Its troops are weary after more than two years of fighting.

Tens of thousands have been grievously wounded.

And the military is struggling to replenish ranks.

On our recent trip to Ukraine, producer Sam Lane and I reported on both of those challenges.

For 22-year old soldier Ivan Kovalyk, these small steps are a huge leap forward in his recovery.

Last September, on the front lines in Eastern Ukraine, he was picking up equipment with a fellow soldier, and was hit in a Russian strike.

IVAN KOVALYK, Ukrainian Amputee (through translator): It was a small projectile, but it flew right at us.

It just happened to find us.

AMNA NAWAZ: It took three excruciating hours to evacuate Kovalyk.

IVAN KOVALYK (through translator): To be honest, I don't remember much.

I was in and out of consciousness.

My friends tried to cheer me up so I didn't fall asleep.

AMNA NAWAZ: By the time he received treatment, both legs needed to be amputated.

About a month ago, he receive a coveted and rare spot here at the Superhumans Center in the Western region of Lviv.

Superhumans launched in April 2023, the only facility of its Superhumans launched in April 2023, providing free care to Ukrainians wounded in the war, custom prosthetics, specialized rehabilitation services, psychological treatment, and, most recently, reconstructive surgery.

More than 400 patients have received care here, over 560 prosthetics distributed.

They now average about 70 new patients a month, though thousands apply for a spot.

IVAN KOVALYK (through translator): When I first got here, I immediately felt a good, cheerful atmosphere.

I knew everyone was a specialist in their field.

I trusted them completely.

AMNA NAWAZ: So how are the new legs working out?

IVAN KOVALYK: Beautiful.

AMNA NAWAZ: Beautiful?

IVAN KOVALYK: Yes.

(LAUGHTER) AMNA NAWAZ: What can you do now?

What are you working on?

IVAN KOVALYK: All.

AMNA NAWAZ: Everything.

IVAN KOVALYK: I can walk.

I can ride with my friends.

I can study.

AMNA NAWAZ: Everything you used to do before.

IVAN KOVALYK Yes.

AMNA NAWAZ: Vitalii Marchenko has worked as a physical therapist for years.

But the injuries coming to Superhumans are unlike any he's ever treated.

VITALII MARCHENKO, Physical Therapist, Superhumans Center (through translator): This is really a completely different category that requires a lot of knowledge.

Ukraine wasn't ready for this kind of rehabilitation before the war.

That's why I'm here.

It's difficult work seeing what my fellow countrymen are going through.

But I understand I'm using my strengths to make sure their rehabilitation happens quickly and effectively.

AMNA NAWAZ: There are an estimated 20,000 amputees in Ukraine today as a result of Russia's war.

Ukraine is also now the most heavily mined country on the planet.

By the end of this year, there could be some 50,000 Ukrainians in need of prosthetics.

SVITLANA KUTSENKO, Head of Mental Health Rehabilitation, Superhumans Center: The demand is growing.

And since the war has not stopped, we will always have to deal with a certain shortage.

AMNA NAWAZ: Svitlana Kutsenko is the head of mental health rehabilitation at Superhumans.

SVITLANA KUTSENKO: When they get their injuries, it's not only about their bodies.

It's also the image of their body that they lose and the feeling that they are incapable of doing things they are used to do.

Our task is to help them to accept their new image.

The second focus is that we should enable them and show them that they are still capable of many other things that they can do in their lives, and that this is not the end.

AMNA NAWAZ: Russia has intensified it's air campaign in recent months and is reportedly preparing for another offensive in late spring or summer.

Beleaguered Ukrainian forces hope that a $60 billion U.S. aid package will help.

But no amount of money can solve one of Kyiv's biggest problems, a shortage of fighters.

A Ukrainian military commander on the eastern front recently said his troops were outnumbered by as many as 10-1.

Last month, President Volodymyr Zelenskyy signed measures aimed at bolstering the ranks, including lowering the draft age from 27 to 25.

For Oleksii Melashchenko, that means contemplating a different future.

The Kyiv-based real estate agent turns 24 soon.

Thousands of young men before him fled Ukraine to avoid conscription.

When you think about if you were called up and you had to join the military, how different would your life in the military be from your daily life right now?

OLEKSII MELASHCHENKO, Real Estate Agent: Of course, it'll be different, I'm sure.

AMNA NAWAZ: Yes?

Have you thought about that, about what it would look like and feel like?

OLEKSII MELASHCHENKO: Yes, yes, sure.

I think you will feel a bit afraid, a bit cold, and maybe noisy, especially noisy.

AMNA NAWAZ: But he says he has no plans to leave, nor do his friends.

OLEKSII MELASHCHENKO: Of course I'm afraid.

It's normal, in my opinion.

Only a stupid person's not afraid.

But if it will be our duty and it's time to go, then time to go.

AMNA NAWAZ: Superhumans' Svitlana Kutsenko says many young Ukrainians coming of age in the war will view their future through a different lens than generations past.

SVITLANA KUTSENKO: This is the generation that grew up knowing that you have to fight for your freedom and you have to fight for your identity.

But once it's obtained in the fight, it's valued much more than anything else.

AMNA NAWAZ: When Ivan Kovalyk first arrived at Superhumans, he was told he'd need a year to walk without crutches.

He did it in just a month.

IVAN KOVALYK (through translator): I said, when, if not now?

Let's try it.

Even if it doesn't work, it'll be my little attempt.

So it's not perfect yet, but I will keep improving.

AMNA NAWAZ: He says if allowed, he wants to return to the military to teach new soldiers about perseverance even after a loss.

A lot of people won't understand how you can be so optimistic about your future, when you have been through so much at such a young age.

What would you say to them?

IVAN KOVALYK (through translator): I have always been cheerful, but when I got a second chance at life, I decided I would live it to the fullest.

There's no reason to be sad.

These are my same legs, just a little different.