#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
#define pb push_back
#define mp make_pair
#define rep(i,n) for(int i=0;i<(n);++i)

int main(){
	cin.tie(0);
	ios::sync_with_stdio(false);
	int n;cin >> n;
	vector<int> A(10);
	rep(i,n){
		int a,b,c;cin >> a >> b >> c;
		A[a-1]++;
		A[b-1]++;
		A[c-1]++;
	}
	int ans=0;
	rep(i,10){
		ans+=A[i]/2;
		A[i]%=2;
	}
	int cnt=0;
	rep(i,10){
		cnt+=A[i];
	}
	ans+=cnt/4;
	cout << ans << endl;
}