#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,prevx=-11,prevy=-11,count=1,count1=1;
    cin >> n;
    for(int a0 = 0; a0 < n; a0++){
        int x;
        int y;
        if(prevx!= -11 && prevy!= -11)
        {
            prevx=x;
            prevy=y;
        }
        cin >> x >> y;
          if(prevx == -11 && prevy== -11)
          {
              prevx=x;
              prevy=y;
              continue;
          }
        if(prevx == x) count++;
        if(prevy == y) count1++;
    }
    if(count == n ||count1 == n) cout<<"YES";
    else cout<<"NO";
    return 0;
}