import sys
import collections

sys.setrecursionlimit(10 ** 8)

input = sys.stdin.readline


def main():
    N = int(input())
    ABC = [[int(x) for x in input().split()] for _ in range(N)]

    cnt = collections.Counter()

    for a, b, c in ABC:
        cnt[a] += 1
        cnt[b] += 1
        cnt[c] += 1

    ans = 0
    mod = 0
    for k in cnt.keys():
        ans += cnt[k] // 2
        mod += cnt[k] % 2

    print(ans + mod // 4)


    

if __name__ == '__main__':
    main()