N = int(input())
dicts = {i:0 for i in range(1, 11)}
for i in range(N):
    a, b, c = map(int, input().split())
    dicts[a] += 1
    dicts[b] += 1
    dicts[c] += 1

ans = 0
rest = 0
for i in range(1, 11):
    ans += dicts[i] // 2
    rest += dicts[i] % 2
print(ans + rest // 4)