from collections import defaultdict

n = int(input()) # 敵を倒す回数
item = defaultdict(int)

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

remain_items = 0 # 同じアイテムを作れないものの個数
n_powerup = 0 # パワーアップ回数

for amount in item.values():
    n_powerup += amount // 2
    remain_items += amount % 2

n_powerup += remain_items // 4

print(n_powerup)