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

n = int(input())
a = [0] * n
b = [0] * n
c = [0] * n
for i in range(n):
    a[i],b[i],c[i] = map(int,input().split())

item = [0,0,0,0,0,0,0,0,0,0]

for i in range(n):
    item[a[i]-1] += 1
    item[b[i]-1] += 1
    item[c[i]-1] += 1

power = 0

for i in range(10):
    power += item[i] // 2
    item[i] -= (item[i] // 2) * 2

power += sum(item) // 4

print(power)