#include <bits/stdc++.h>
using namespace std;
using ll = long long;

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    int m;
    cin >> m;
    map<int,int> mp;
    for(int i = 0; i < m; i++){
        int a, b, c;
        cin >> a >> b >> c;
        mp[a]++, mp[b]++, mp[c]++;
    }
    int v2 = (*mp.begin()).second;
    for(auto [key, v] : mp){
        if(v != v2){
            cout << "NO\n";
            return 0;
        }
    }
    cout << "YES\n";
}