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

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n;
    cin >> n;
    vector<pair<int,int>> a(n);
    for(auto &&[s, t] : a) cin >> s >> t;
    sort(a.begin(), a.end());
    for(int i = 0; i < n; ){
        int p = i;
        while(i < n && a[p].first == a[i].first) i++;
        for(int j = p; j + 1 < i; j++){
            if(a[j].second != a[j + 1].second){
                cout << "No\n";
                return 0;
            }
        }
    }
    cout << "Yes\n";
}