#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < n; i++)
using namespace std;

int n;
int x[10];

int main(){
	scanf("%d",&n);
	rep(i,n){
		int a,b,c;
		scanf("%d%d%d",&a,&b,&c);
		a--; b--; c--;
		x[a]++; x[b]++; x[c]++;
	}
	int ans = 0;
	rep(i,10){
		ans += x[i]/2;
		x[i] %= 2;
	}
	int sum = 0;
	rep(i,10) sum += x[i];
	ans += sum/4;
	printf("%d\n", ans);
}