#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;
    int a[n]={0};
    int b[n]={0};
    int x;
        int y;
        
    for(int i = 0; i < n; i++){
        cin >> x >> y;
        a[i] = x;
        b[i] = y;
    }
    
    int fx=0,fy=0;
    for(int i=0;i+1<n;i++){
        if(a[i]!=a[i+1]){
            fx=1;
            break;
        }
    }
    if(fx==1){
    for(int i=0;i+1<n;i++){
        if(b[i]!=b[i+1]){
            fy=1;
            break;
        }
    }
    }
    if(fx==0 || fy==0)
            cout<<"YES";
    else cout<<"NO";
    return 0;
}