#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[10],y[10],a=0,b=0;
    cin >> n;
    for(int a0 = 0; a0 < n; a0++){
        //int x;
        //int y;
        cin >> x[a0] >> y[a0];
        //if()
    }
    for(int a0 = 0; a0 < n-1; a0++){
        if(x[a0]==x[a0+1]){a++;}
        if(y[a0]==y[a0+1]){b++;}
    }
    if(a==n-1 || b==n-1){
        cout << "YES" << endl;
    }
    else{
         cout << "NO" << endl;        
    }
    return 0;
}