#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;
    int count1=1,count=1;
    cin >> n;
    int x,prevx=-20;
    int y,prevy=-20;
    for(int a0 = 0; a0 < n; a0++){
        cin >> x >> y;
        if(a0==0){
            prevx=x;
            prevy=y;
        }
        else{
            if(prevx==x){
                prevx=x;
                count++;
            }
            if(prevy==y){
                prevy=y;
                count1++;
            }
        }
    }
    if(count==n || count1==n){
        cout << "YES" <<endl;
    }
    else{
        cout << "NO" <<endl;
    }
    return 0;
}