#include <stdio.h>
#include <bits/stdc++.h>
#include <atcoder/all>
using namespace atcoder;
using mint = modint998244353;
using namespace std;
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define Inf 100000001

int main(){
	
	int n;
	cin>>n;
	
	vector<int> cnt(11,0);
	rep(i,n){
		int a,b,c;
		cin>>a>>b>>c;
		cnt[a]++;
		cnt[b]++;
		cnt[c]++;
	}
	
	int ans = 0;
	int t = 0;
	rep(i,11){
		ans += cnt[i]/2;
		t += cnt[i]%2;
	}
	ans += t/4;
	
	cout<<ans<<endl;
	return 0;
}