N = int(input()) cnt = [0] * 11 for i in range(N): items = list(map(int, input().split())) for j in range(3): cnt[items[j]] += 1 ans = 0 res = 0 for i in range(1, 11): ans += cnt[i] // 2 res += cnt[i] % 2 ans += res // 4 print(ans)