That's the problem Russia is facing from the beginning.
Putin don't have enough troop to finish the job, he should have known that by April when they were forced to retreat from Kyiv. And if he were to continue with this war then, he should have at least partially mobilised his troop back then, then you get 3 to 6 months training, then you send them to Ukraine. That way, they will have a chance.
On the other hand, Ukraine has been following a rigorous regime to train up new troop, Europe alone is training around 100,000 Ukrainian a year. Then armed them and ready them for the war. Ukraine itself probably can generate around 350 - 400,000 troop a single year, and they have been doing that since day 1.
Not much of a chance when you send someone who probably had already forgotten which end the bullet comes out, give them 5 days training and ship them to the front. They would not even made a punching bag for the Ukrainian....