from collections import Counter

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

ans = 0
for k, v in freq.items():
    d, m = divmod(v, 2)
    ans += d
    freq[k] = m

ans += sum(freq.values()) // 4
print(ans)