#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,i,j,count=0,count1=0;
    cin >> n;
   int a[n];
    int b[n];
    for(i=0;i<n;i++)
        {
        cin>>a[i];
        cin>>b[i];
    }
    for(i=0;i<n-1;i++)
        {
        if(a[i]==a[i+1])
            {
            count++;
        }
    }
    for(i=0;i<n-1;i++)
        {
            if(b[i]==b[i+1])
                {
                count1++;
            }
        }
    if(count+1==n || count1+1==n)
        {
        cout<<"YES"<<endl;
    }
    else
        {
        cout<<"NO"<<endl;
    }
    return 0;
}