function Main(input) {
	input = input.split("\n");
	tmp = input[0].split(" ");
	var a = parseInt(tmp[0], 10);
	var b = parseInt(tmp[1], 10);
	var c = parseInt(tmp[2], 10);
	var answer = 0;
	if(c > a-b){
      answer = c-(a-b);
    }else{
      answer = 0;
    }
	console.log(answer);
}
Main(require("fs").readFileSync("/dev/stdin", "utf8"));