#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<pair<int,int> > k;
    vector<pair<int,int> > t;
    for(int a0 = 0; a0 < n; a0++){
        int x;
        int y;
        cin >> x >> y;
        k.push_back(make_pair(x,y));
        t.push_back(make_pair(y,x));
    }
    sort(k.begin(),k.end());
    sort(t.begin(),t.end());
    if(k[0].first==k[n-1].first||t[0].first==t[n-1].first)
           cout<<"YES"<<endl;
    else
            cout<<"NO"<<endl;       
    return 0;
}