#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 first, second, xfine = 1, yfine = 1;
    cin>>first>>second;
    for(int a0 = 1; a0 < n; a0++)
    {
        int x;
        int y;
        cin >> x >> y;
        if(first != x)
            xfine = 0;
        if(second != y)
            yfine = 0;
    }
    if((xfine==0 && yfine==1) || (xfine==1 && yfine==0) || (xfine==1 && yfine==1))
        cout<<"YES";
    else
        cout<<"NO";
    return 0;
}