#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,c=0,r=0;
    vector < pair < int ,int >>v;
    cin >> n;
    for(int a0 = 0; a0 < n; a0++){
        int x;
        int y;
        cin >> x >> y;
        v.push_back(make_pair(x,y));
    }
    for(int i=0;i<n-1;i++)
        {
        if(v[i].first==v[i+1].first)
            {
           // cout<<v[i].first<<"\n";
            c++;
        }
        if(v[i].second==v[i+1].second)
            {
            r++;
        }
    }
   // cout<<c<<" "<<r<<"\n";
    if(r==n-1 || c==n-1)
        cout<<"YES\n";
    else
        cout<<"NO\n";
    return 0;
}