import bisect import copy import decimal import fractions import heapq import itertools import math import random import sys from collections import Counter, deque,defaultdict from functools import lru_cache,reduce from heapq import heappush,heappop,heapify,heappushpop,_heappop_max,_heapify_max def _heappush_max(heap,item): heap.append(item) heapq._siftdown_max(heap, 0, len(heap)-1) def _heappushpop_max(heap, item): if heap and item < heap[0]: item, heap[0] = heap[0], item heapq._siftup_max(heap, 0) return item from math import gcd as GCD read=sys.stdin.read readline=sys.stdin.readline readlines=sys.stdin.readlines N=int(readline()) items=[0]*10 for _ in range(N): a,b,c=map(int,readline().split()) a-=1;b-=1;c-=1 items[a]+=1 items[b]+=1 items[c]+=1 ans=0 for i in range(10): ans+=items[i]//2 items[i]%=2 ans+=sum(items)//4 print(ans)