#include <map>
#include <set>
#include <list>
#include <cmath>
#include <ctime>
#include <deque>
#include <queue>
#include <stack>
#include <string>
#include <bitset>
#include <cstdio>
#include <limits>
#include <vector>
#include <climits>
#include <cstring>
#include <cstdlib>
#include <fstream>
#include <numeric>
#include <sstream>
#include <iostream>
#include <algorithm>
#include <unordered_map>

using namespace std;


int main(){
    int n;
    cin >> n;
    //map<int, int> xpoints;
    //map<int, int> ypoints;
    bool diffX = false;
    bool diffY = false;
    int prevX;
    int prevY;
    for(int a0 = 0; a0 < n; a0++){
        int x;
        int y;
        cin >> x >> y;
        //xpoints[x] = xpoints[x] + 1;
        //ypoints[y] = ypoints[y] + 1;
        if (a0 == 0) {
            prevX = x;
            prevY = y;
        } else {
            if (prevX != x) diffX = true;
            if (prevY != y) diffY = true;
            prevX = x;
            prevY = y;
        }
    }
    //cout << "X " << xpoints[0] << " | " << n << " | " << xpoints.size() << endl;
    /*if (xpoints.size() < n) {
        cout << "YES" << endl;
    } else if (ypoints.size() < n) {
        cout << "YES" << endl;*/
    
    if (!diffX || !diffY) {
        cout << "YES" << endl;
    } else {
        cout << "NO" << endl;
    }
    return 0;
}