from collections import defaultdict


def main():
    n = int(input())
    d = defaultdict(int)
    for _ in range(n):
        a, b, c = map(int, input().split())
        d[a] += 1
        d[b] += 1
        d[c] += 1

    ans = 0
    left = 0
    for k, v in d.items():
        ans += v // 2
        left += v % 2
    ans += left // 4
    print(ans)

if __name__ == '__main__':
    main()