#include <map>
#include <set>
#include <list>
#include <cmath>
#include <ctime>
#include <deque>
#include <queue>
#include <stack>
#include <string>
#include <bitset>
#include <cstdio>
#include <limits>
#include <vector>
#include <climits>
#include <cstring>
#include <cstdlib>
#include <fstream>
#include <numeric>
#include <sstream>
#include <iostream>
#include <algorithm>
#include <unordered_map>

using namespace std;


int main(){
    vector < pair <int,int> > a(10);
    int i;
    int n;
    cin>>n;
    for(i=0;i<n;++i)
        {
        cin>>a[i].first;
        cin>>a[i].second;
    }
int flag1=0,flag2=0;
    for(i=0;i<n-1;++i)
        {
        if(a[i].first!=a[i+1].first)
            {
            flag1=1;
        }
        if(a[i].second!=a[i+1].second)
            {
            flag2=1;
        }
                   
        }
if(flag1==0)
    cout<<"YES";
    else if(flag2==0)
        cout<<"YES";
        else
        cout<<"NO";
}