function Main(input) {
  input = input.script(" ").map(Number);
  
  var A = input[0];
  var B = input[1];
  var C = input[2];
  
  var ans = C - (A - B);
  
  if (ans < 0) ans = 0;
  
  console.log(ans);
}

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