'use strict';

function main(stdin) {
  const input = stdin.split(' ').map(v => parseInt(v, 10));
  const A = input[0];
  const B = input[1];
  const C = input[2];
  console.log(Math.max(C - (A - B), 0));
}

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