I repaid an overpayment debt to the Government last year, how do I claim that on my taxes?

I received an overpayment while in the military which I've been paying back. I received a letter from the military saying I paid off $1,900 est of that repayment and I can claim that on my taxes. I plan on filing my taxes online (Turbotax/H&R Block) and I want to know where I can input this information.