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

using lint = long long;

int main() {
    int n;
    cin >> n;
    vector<int> cnt(10);
    rep(i, n) {
        int a, b, c;
        cin >> a >> b >> c;
        a--;
        b--;
        c--;
        cnt[a]++;
        cnt[b]++;
        cnt[c]++;
    }
    int ans = 0;
    rep(i, 10) {
        ans += cnt[i] / 2;
        cnt[i] %= 2;
    }
    ans += accumulate(ALL(cnt), 0) / 4;
    cout << ans << endl;
}