#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;
    vector <int>hor;
    vector <int>l;
    for(int a0 = 0; a0 < n; a0++){
        int x;
        int y;
        cin >> x >> y;
        hor.push_back(x);
        l.push_back(y);
    }
    int q=l[0],p=hor[0],c=0,k=0;
    for(int i=0;i<n;i++)
        {
        if(hor[i]==p)
            {
            c++;
        }
        if(l[i]==q)
            {
            k++;
        }
    }
    if(c!=k){
    if(c==n||k==n){
        cout<<"YES";
    }
        else{
            cout<<"NO";
        }}
    else{
        cout<<"NO";
    }
    return 0;
}