# -*- coding:utf-8 -*-
if __name__ == '__main__':
    n = input()
    an = input().split()
    ans = set(an)
    l = {}
    for a in an:
        if a in l.keys():
            l[a] += 1
        else:
            l[a] = 1
    print(len(tuple(k for k, v in l.items() if v == 1)))