#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,vert,hor;
    cin >> n;
    vert = 1;
    hor = 1;
    int bx,by;
    for(int a0 = 0; a0 < n; a0++){
        int x;
        int y;
        cin >> x >> y;
        if(a0 == 0){
            bx = x;
            by = y;
        }
        else{
            if(x!=bx) vert = 0;
            if(y!=by) hor = 0;
        }
    }
    if(vert||hor) cout<<"YES"<<'\n';
    else cout<<"NO"<<'\n';
    return 0;
}