//Ishan Bansal
//handle:ishan.nitj at codeforces ,ishan_nitj at codechef
#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define inf 1000000000000000000
#define MOD 1000000007
#define rep(i,n) for(i=0;i<n;i++)
#define print_array(a,n) for(i=0;i<n;i++) printf("%lld ",a[i]);
#define mset(x,v) memset(x, v, sizeof(x))
#define dbg1(x) cout<<#x<<" "<<x<<endl;
#define dbg2(x,y) cout<<#x<<" "<<x<<" "<<#y<<" "<<y<<endl;
#define dbg3(x,y,z) cout<<#x<<" "<<x<<" "<<#y<<" "<<y<<" "<<#z<<" "<<z<<endl;
#define dbg4(x,y,z,k) cout<<#x<<" "<<x<<" "<<#y<<" "<<y<<" "<<#z<<" "<<z<<" "<<#k<<" "<<k<<endl;
#define pb push_back
#define fe first
#define se second
#define mag 12
ll dp[51][51];

int main(){
//std::ios::sync_with_stdio(false);
//cin.tie(0);
//freopen("OP.txt","r",stdin);
//freopen("IP.txt","w",stdout);
ll n,i;cin>>n;
set<ll>s1,s2;
rep(i,n){
ll x,y;cin>>x>>y;
s1.insert(x);s2.insert(y);
}
if(s1.size()==1 || s2.size()==1)
cout<<"YES";
else
cout<<"NO";
}