function Main(input) {
    var idata = input.split(" ").map(Number);
    // var idata = input.split(/\s/);
    var a = idata[0];
    var b = idata[1];
    var c = idata[2];
    var ans = Math.max(0, c - (a - b));
    console.log(ans);
}

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