#include <iostream>

using namespace std;


int main(){
    int n;
    cin >> n;
    bool hor = true;
    bool ver = true;
    bool allSame = true;
    int x;  //1st x coordinate
    int y;  //1st y coordinate
    cin >> x >> y;
    for(int a0 = 1; a0 < n; a0++){
        int nextX;  //x coordinate
        int nextY;  //y coordinate
        cin >> nextX >> nextY;
        if(x != nextX) hor = false;
        if(y != nextY) ver = false;
        if(x != nextX || y != nextY) {
            allSame = false;
        }
    }
    if((hor || ver) && !allSame) cout << "YES" << endl;
    else cout << "NO" << endl;
    return 0;
}