from collections import defaultdict
A = defaultdict(int)   # 初期値が [] （空リスト）
# https://pcnote.henchoko.com/?p=965


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

r, s = 0, 0
for key, val in A.items():
    r += val //2
    s += val %2
r += s//4
print(r)