from collections import *
from functools import *
from itertools import *
from heapq import *
import sys,math
input = sys.stdin.readline

N = int(input())
X = [0]*11
for _ in range(N):
    a,b,c = map(int,input().split())
    X[a] += 1
    X[b] += 1
    X[c] += 1
ans = 0
for i in range(11):
    ans += X[i]//2
    X[i] = X[i]%2

print(ans + sum(X)//4)