#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 a[1000],b[1000];
    for(int ao = 0; ao < n; ao++){
       cin>>a[ao]>>b[ao];
    }
    int c=0,c1=0,i;
    for(i=0;i<n-1;i++)
        {
        if(a[i]==a[i+1])
            c++;
        else if(b[i]==b[i+1])
            c1++;
    }
    if(c==n-1 || c1==n-1)
    cout<<"YES"<<endl;
    else
        cout<<"NO"<<endl;
    return 0;
}