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

#define sin(x) scanf("%d",&x)
#define sin2(x,y) scanf("%d%d",&x,&y)
#define sin3(x,y,z) scanf("%d%d%d",&x,&y,&z)

#define pb push_back
#define mp make_pair
#define y1 asdnqw
#define next mdamdamda
#define right praviy
#define x first
#define y second
#define kub(x) ((x)*(x)*(x))
#define ld double
#define ll int
const double eps=0.1;
const int N=105123;
int n,q,w;
 int main(){
    cout.precision(3);
     //cin.tie(0);
    // ios_base::sync_with_stdio(0);
    set<int> x,y;
    cin>>n;
    for(int i=1;i<=n;++i){
        cin>>q>>w;
        x.insert(q);
        y.insert(w);
    }
    if(x.size()==1||y.size()==1)cout<<"YES";
    else cout<<"NO";



}