function Main(input) {
  input = input.trim()
  var arr = input.split("\n");
  var N = input[0];
  arr.shift();
  arr = arr.sort();
  var sum = 1;
  for(var i=1;i<N;i++){
    if(arr[i-1]!==arr[i]){
      sum++;
    }
  }
  console.log(sum);
}Main(require("fs").readFileSync("/dev/stdin", "utf8"));