#include <bits/stdc++.h>
#define  re(i,j,n) for(li i=(j);i<(n);i++)
#define  rep(i,n) re(i,0,(n))
#define  all(a) begin(a),end(a)
#define  pb push_back
using namespace std;
typedef long int li;
typedef unsigned long long ull;
typedef vector<int> vi;
typedef vector<li> vli;
typedef vector<string> vs;


int main()
{
    int n,a[10]={0},ans=0,r=0;
    cin>>n;
    rep(i,n*3){
        int x;
        cin>>x;
        a[x-1]++;
    }
    rep(i,10){
        ans+=a[i]/2;
        r+=a[i]%2;
    }
    cout<<ans+r/4<<endl;
    return 0;
}