function Main(input) {
	input = input.split("\n");
	const input1 = input[0].split(" ")
	const A = parseInt(input1[0])
	const B = parseInt(input1[1])
	const C = parseInt(input1[2])
	const result = A-B > C ? 0 : C - (A-B)
	console.log(result)

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