#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 a[100],b[100],i,n;
    ios::sync_with_stdio(false);
    cin >> n;
    for(i=0;i<n;i++)
        cin >> a[i] >> b[i] ;
    sort(a,a+n);
    sort(b,b+n);
    if(a[0]==a[n-1])
        cout <<"YES" << endl;
    else if((b[0]==b[n-1]))
        cout <<"YES" << endl;
    else
        cout << "NO" << endl;
    return 0;
}