#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[n],y[n],count1=0,count2=0,x1,y1;
    for(int a0 = 0; a0 < n; a0++){
        
        cin >> x[a0] >> y[a0];
        x1=x[0];
        y1=y[0];
        if(x[a0]==x1)
            count1++;
        if(y[a0]==y1)
            count2++;
    }
    if(count1==n || count2==n)
        cout<<"YES";
    else
        cout<<"NO";
    return 0;
}