#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 cx=0,cy=0,c1x,c1y;
    for(int a0 = 0; a0 < n; a0++){
        int x;
        int y;
        cin >> x >> y;
        if(a0==0){
            c1x=x;
            c1y=y;
        }else{
            if(c1x!=x) cx=1;
            if(c1y!=y) cy=1;
        }
        
        
    }
    if(cx==0 || cy==0) cout<<"YES"<<endl;
    else cout<<"NO"<<endl;
    return 0;
}