#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;
    int arr1[n],arr2[n],i;
    for(i=0;i<n;i++)
    {
        cin>>arr1[i]>>arr2[i];
    }
    int ans1=1,ans2=1;
    for(i=0;i<n-1;i++)
    {
        if(arr1[i]==arr1[i+1])
            ans1++;
        if(arr2[i]==arr2[i+1])
            ans2++;        
    }
    if(ans1==n || ans2==n)
        cout<<"YES"<<endl;
    else
        cout<<"NO"<<endl;
    return 0;
    
}