#include <bits/stdc++.h>

#define ll long long
#define ld long double
#define rep(i,a,b) for (int i = a; i < b; i++)
#define irep(i,a,b) for (int i = a; i > b; i--)
#define print(n) cout << n << endl
#define rup(a,b) (a+b-1)/b

using namespace std;

int d[11];
int main(){
    cout << fixed << setprecision(15);
    int N;
    cin >> N;
    int a,b,c;
    rep(i,0,N) {
        cin>>a>>b>>c;
        d[a] += 1;
        d[b] += 1;
        d[c] += 1;
    }
    int count = 0;
    int now = 0;
    int p;
    rep(i,1,11){
        p = (int)(d[i] / 2);
        count += p;
        d[i] %= 2;
        now += d[i];
    }
    count += now/4;
    print(count);

    
    system("pause");
    return 0;
}