N = int(input())
cnt = [0] * 11
for _ in range(N):
    a,b,c = map(int,input().split())
    cnt[a] += 1
    cnt[b] += 1
    cnt[c] += 1
ans = 0
for i in range(11):
    ans += cnt[i] // 2
    cnt[i] %= 2
ans += sum(cnt) // 4
print(ans)