#include <bits/stdc++.h>
#include <algorithm>

#define pb push_back
#define mp make_pair
#define mt make_tuple
#define ll long long
#define pii pair<int,int>
#define tii tuple <int,int,int>
#define N 1000005
#define mod 2000003
#define X first
#define Y second
#define eps 0.0000000001
#define all(x) x.begin(),x.end()
#define tot(x) x+1,x+n+1
using namespace std;
int x,y,i,n;
set<int>s,t;
int main()
{
    cin.sync_with_stdio(0);
    cout.sync_with_stdio(0);
    cin>>n;
    for(i=1; i<=n; i++)
    {
        cin>>x>>y;
        s.insert(x);
        t.insert(y);
    }
    if(s.size()==1||t.size()==1)
        cout<<"YES";
    else
        cout<<"NO";
    return 0;
}