#include<iostream>
#include<vector>
#include<algorithm>
#include<cstdio>
#include<cmath>
#include<string>
using namespace std;
int main(){
    int n,a,b,c,table[11]={},sum=0,ans=0;
    cin >> n;
    while(n--){
        cin >> a >> b >> c;
        table[a]++;
        table[b]++;
        table[c]++;
    }
    for(int i=1;i<=10;i++){
        ans += (table[i]/2);
        sum += (table[i]%2);
    }
    ans += (sum/4);
    cout << ans;
    return 0;
}