"use strict";
const Main = (input) =>{
   let xs = input.trim().split(' ');
   let a = xs[0] - xs[1];
   let b = xs[2] - a;
   if(b <= 0){
   console.log(0);
   }else{
   console.log(b);
   }

}
Main(require('fs').readFileSync('/dev/stdin','utf8'));