function Main(input) {
  input = input.split(" ");
  //console.log(input);
  kido(input[0], input[1], input[2]);
  
}

function kido(a, b, c) {
  a = parseInt(a);
  b = parseInt(b);
  c = parseInt(c);
	if (b + c < a) {
		var ans = 0;
		
	} else {
		var ans = (b + c) - a;
		
	}
	
	console.log(ans);
	
}

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