# -*- coding: utf-8 -*-

import sys
from collections import Counter

def input(): return sys.stdin.readline().strip()
def list2d(a, b, c): return [[c] * b for i in range(a)]
def list3d(a, b, c, d): return [[[d] * c for j in range(b)] for i in range(a)]
def list4d(a, b, c, d, e): return [[[[e] * d for j in range(c)] for j in range(b)] for i in range(a)]
def ceil(x, y=1): return int(-(-x // y))
def INT(): return int(input())
def MAP(): return map(int, input().split())
def LIST(N=None): return list(MAP()) if N is None else [INT() for i in range(N)]
def Yes(): print('Yes')
def No(): print('No')
def YES(): print('YES')
def NO(): print('NO')
sys.setrecursionlimit(10 ** 9)
INF = 10 ** 18
MOD = 10 ** 9 + 7

N = INT()
C = Counter()
for _ in range(N):
    a, b, c = MAP()
    C[a] += 1
    C[b] += 1
    C[c] += 1

cnt = ans = 0
for v in C.values():
    d, m = divmod(v, 2)
    ans += d
    cnt += m
ans += cnt // 4
print(ans)