#!/usr/bin/env python
#coding:utf8

def read():
    raw_input()
    return map(int, raw_input().split())


def work(vList):
    vList.sort()

    ans = 0
    idx = 0
    while idx < len(vList):
        if idx == len(vList) - 1 or vList[idx] != vList[idx + 1]:
            ans += 1
        while idx + 1 < len(vList) and vList[idx] == vList[idx + 1]:
            idx += 1
        idx += 1

    print ans


if __name__ == "__main__":
    work(read())