n = int(input())
cnt = [0 for i in range(10)]
for i in range(n):
    a, b, c = map(int, input().split())
    cnt[a - 1] += 1
    cnt[b - 1] += 1
    cnt[c - 1] += 1
ans = 0
cnt2 = 0
for i in cnt:
    ans += i // 2
    if i % 2 == 1:
        cnt2 += 1
ans += cnt2 // 4
print(ans)