#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 *x=new int[n];
    int *y=new int[n];
    for(int a0 = 0; a0 < n; a0++){
        
        cin >> x[a0] >> y[a0];
   
    }
    int a=x[0],b=y[0],c1=0,c2=0;
    for(int i=0;i<n;i++){
        if(x[i] == a)
            c1++;
        else if(y[i] == b)
            c2++;
    }
    if(c1 == n || c2 == n)
        cout<<"YES";
    else
        cout<<"NO";
        
    return 0;
}