#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;
    int y;cin>>x>>y;bool cx = true,cy = true;
    for(int a0 = 0; a0 < n-1; a0++){
        int p,q;
        cin >> p >> q;
        if(p!=x)
            cx = false;
        if(q!=y)
            cy = false;
    }
    if(cx || cy)
        cout<<"YES";
    else
        cout<<"NO";
    return 0;
}