#include <bits/stdc++.h>
using namespace std;

struct point {
    int x, y;
} A[100];

int main()
{
	ios::sync_with_stdio(0); cin.tie(0);
	int n, i;
	bool okx = 1, oky = 1;
	cin>>n;
	for(i=0;i<n;++i) cin>>A[i].x>>A[i].y;
	for(i=1;i<n;++i)
    {
        if(A[i].x != A[i-1].x)
            okx = 0;
        if(A[i].y != A[i-1].y)
            oky = 0;
    }
    cout<<( okx or oky ? "YES\n" : "NO\n");
	return 0;
}