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

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

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