function Main (input) {
  input = input.split("\n");
  var N = parseInt(input[0], 10);
  input.pop();
  input.shift();
  var S = input;
  var E = [];
  var ans = 0;
  for (var i of S) {
    if (!(E.some(inp => inp == i))) {
      ans++;
    }
    E.push(i);
  }
  console.log(ans);
}

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