#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,a[101],b[101],f = 0,f1 = 0,i,x,y;
    cin >> n;
    for(int a0 = 0; a0 < n; a0++){
        cin >> x >> y;
        a[a0] = x;
        b[a0] = y;
    }
    x = a[0];
    y = b[0];
    for(i=1;i<n;i++)
    {
        if(a[i] != x)
          f = 1;
        if(b[i] != y)
          f1 = 1;
    }
    if(f == 0 || f1 == 0)
        cout<<"YES";
    else
        cout<<"NO";
    return 0;
}