function main(input) {
  const args = input.split("\n");
  const N = args[0],
    nums = args.slice(1, args.length - 1);

  // console.log(nums.filter((n, i)=> nums.indexOf(n) === i).length);
  console.log(Array.from(new Set(nums)).length);
}
main(require("fs").readFileSync("/dev/stdin", "utf8"));