#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;
    int xo,yo,x,y;
     bool xx=true,yy=true;
    cin>>n;
    n--;
    cin>>x>>y;
    xo=x;
    yo=y;
    while(n--)
        {
        cin>>x>>y;
        if(x!=xo)
            xx=false;
        if(y!=yo)
            yy=false;
    }
    if(xx||yy)
        cout<<"YES";
    else cout<<"NO";
    
    
}