#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 xs[n],index=0,count1=0,count2=0;
    int ys[n];
    for(int a0 = 0; a0 < n; a0++){
        int x;
        int y;
        cin >> x >> y;
        xs[a0]=x;
        ys[a0]=y;
       
    }
    for(int i=1;i<n;i++){
        if(xs[i]==xs[i-1]){
            count1++;
        }
        if(ys[i]==ys[i-1]){
           count2++; 
        }
    }
    if(count1==n-1 || count2==n-1){
        cout<<"YES"<<endl;
    }
    else{
        cout<<"NO"<<endl;
    }
    return 0;
}