#include "bits/stdc++.h"
using namespace std;

typedef long long Int;
#define REP(i,n) for(int (i)=0;(i)<(int)(n);++(i))

int main() {
	int n; cin >> n;
	int item[10] = {};
	REP(i, n) {
		int a, b, c; cin >> a >> b >> c;
		item[a - 1]++;
		item[b - 1]++;
		item[c - 1]++;
	}
	
	int ans = 0;
	int remain = 0;
	REP(i, 10) {
		ans += item[i] / 2;
		item[i] %= 2;
		remain += item[i];
	}
	ans += remain / 4;
	cout << ans << endl;
}