#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(){
    int n;
    cin >> n;
    long long int a[n],b[n],i,f1=0,f2=0;
    for(i=0;i<n;i++)
    {
        long long int x;
        long long int y;
        cin >> x >> y;
        a[i]=x;
        b[i]=y;
    }
    for(i=1;i<n;i++)
    {
        if(a[i]!=a[i-1])
            f1=1;
        if(b[i]!=b[i-1])
            f2=1;
    }
    if(f1==1&&f2==1)
        cout<<"NO";
    else
        cout<<"YES";
    return 0;
}