#!/usr/bin/env python
# -*- coding:utf-8 -*-

from collections import defaultdict

def main():
    N = input()
    d = defaultdict(int)
    for _ in range(N):
        a, b, c = map(int, raw_input().split())
        d[a] += 1
        d[b] += 1
        d[c] += 1
    powerup_cnt = 0
    remain_items = 0
    for index in d:
        powerup_cnt += d[index] / 2
        remain_items += d[index] % 2
    powerup_cnt += remain_items / 4
    print(powerup_cnt)

if __name__ == "__main__":
    main()