#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;
    bool xChanged = false;
    bool yChanged = false;
    int prevX = -11;
    int prevY = -11;
    for(int a0 = 0; a0 < n; a0++){
        int x;
        int y;
        cin >> x >> y;
        if (a0==0) {
          prevX = x;
          prevY = y;
        }
        if (prevX!=x) { xChanged = true; }
        if (prevY!=y) { yChanged = true; }
        prevX = x;
        prevY = y;
    }
    if (xChanged && !yChanged) { cout << "YES" << endl; }
    else if (!xChanged && yChanged) { cout << "YES" << endl; }
    else { cout << "NO" << endl; }
    return 0;
}