log = console.log;

var stdin = require("fs").readFileSync("/dev/stdin", "UTF-8");
var lines = stdin.split("\n");
var N = lines[0].split(" ").map(Number)[0];
var A = lines
  .slice(1)
  .filter(v => v !== "");

var Aary = Array(10 ^ 9).fill(0)

A.forEach(v=>{
  Aary[v] = Aary[v] === 0 ? 1 : 0  
})

log(Aary.reduce((a,b) => a+b))