#include<bits/stdc++.h>
using namespace std;
#define NUM 11
int main(void){
    int N; cin >> N;
    int a, b, c, cnt = 0;
    int dp[NUM], sub = 0;
    dp[0] = 0;
    for(int i = 1; i < 11; i++){
        dp[i] = 0;
    }
    for(int i = 0; i < N; i++){
        cin >> a >> b >> c;
        dp[a]++; dp[b]++; dp[c]++;
    }
    
    for(int i = 1; i < 11; i++){
        cnt += dp[i] / 2;
        sub += dp[i] % 2;
        if(sub / 4 == 1) {
            cnt++; sub = 0;
            }
    }
    cout << cnt << endl;
    return 0;
}