#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,y;
    cin>>x>>y;
    int x1=x;
    int y1=y;
    for(int a0 = 0; a0 < n-1; a0++){
        int x;
        int y;
        cin >> x >> y;
        
        //cout<<x<<" "<<x1<<" "<<y<<" "<<y1<<"\n";
        if(x!=x1 && y!=y1)
        {cout<<"NO";return 0;}
        
    }
cout<<"YES";
}