#include<bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i=0; i<(n); ++i)
using ll = long long;

int main(){
    int n; cin >> n;
    vector<int> a(11,0);
    rep(i,n*3){
        int x; cin >> x;
        a[x]++;
    }

    int sum = 0;
    int cnt = 0;
    for(int i=1; i<=10; i++){
        sum += (a[i]/2);
        cnt += a[i]%2;
    }

    sum += cnt/4;
    cout << sum << endl;
}