#include<bits/stdc++.h>
using namespace std;
#define max3(a,b,c) max(max(a,b),c)
#define min3(a,b,c) min(min(a,b),c)
#define PI acos(-1.0)
#define LL long long
#define INF_MAX 2147483647
#define INF_MIN -2147483647
#define MX 1000005
#define MOD 1000000007
int main()
{
   //freopen("a.in", "r", stdin);
    //freopen("a.out", "w", stdout);
    int n,x,y;
    set<int>s1;
    set<int>s2;
    while(cin>>n)
    {
        int cntx=0,cnty=0;
        for(int i=0;i<n;i++)
        {
            cin>>x>>y;
            s1.insert(x);
            s2.insert(y);

        }
        if(s1.size()==1|| s2.size()==1)
        {
            cout<<"YES"<<endl;
        }
        else
        {
            cout<<"NO"<<endl;
        }
        s1.clear();
        s2.clear();
    }
}