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