def main():
    N = int(input())
    items = [0] * 10
    lvup = 0
    lvup_c = 0

    for _ in range(N):
        a, b, c = map(int, input().split())
        items[a - 1] += 1
        items[b - 1] += 1
        items[c - 1] += 1

    for i in items:
        if i >= 2:
            lvup += (i // 2)
        elif i == 1:
            lvup_c += 1

    lvup += (lvup_c // 4)

    print(lvup)

if __name__ == '__main__':
    main()