n = int(input())

cnt = {}
for _ in range(n):
  a, b, c = map(int, input().split())
  cnt[a] = cnt.get(a, 0) + 1
  cnt[b] = cnt.get(b, 0) + 1
  cnt[c] = cnt.get(c, 0) + 1

ans = 0
for k, v in cnt.items():
  ans += v // 2
  cnt[k] %= 2

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