#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 x[n];
        int y[n];
    for(int a0 = 0; a0 < n; a0++){
        
        cin >> x[a0] >> y[a0];
    }
    int count=0,kount=0;
    for(int i=1;i<n;i++)
        {
        if(x[i]!=x[i-1])
            count=1;
         if(y[i]!=y[i-1])
            kount=1;
    }
    if(count==0 || kount==0)
        cout<<"YES";
    else 
        cout<<"NO";
    return 0;
}