function main(arg) {
  // var str = arg.trim();
  const array = arg.trim().split("\n");
  const first = array[0].split(" ");
  const N = parseInt(first[0]);
  const d = parseInt(array[1]);
  console.log(N - d);
}
main(require("fs").readFileSync("/dev/stdin", "utf8"));
// main("3 2\n2\n1 3\n1\n3");
//https:/ / atcoder.jp / contests / abc166 / tasks / abc166_a;
