function Main(input) {
    input = input.split(" ");
    var A = parseInt(input[0],10);
    var B = parseInt(input[1],10);
    var C = parseInt(input[2],10);
    if(B + C - A > 0){
        console.log(B + C - A);
    }else{
        console.log(0);
    }
}
Main(require("fs").readFileSync("/dev/stdin", "utf8"));