#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 , x[11] , y[11] , count_x = 0 , count_y = 0;
    cin >> n;
    for(int a0 = 0; a0 < n; a0++){
        cin >> x[a0] >> y[a0];     
    }
    
    for(int i = 1 ; i < n ; ++i){
        if( x[i] == x[i-1])
            count_x++ ;
        if( y[i] == y[i-1])
            count_y++ ;
    }
    if(count_x == n-1 || count_y == n-1 )
        cout << "YES" ;
    else
        cout << "NO" ;
    return 0;
}