#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 f1=0,f2=0;
    vector<pair<int,int>>points;
    for(int a0 = 0; a0 < n; a0++)
    {
        int x;
        int y;
        cin >> x >> y;
        points.push_back(make_pair(x,y));
    }
    for(int i=0;i<n-1;i++)
    {
        if(points[i].first==points[i+1].first)f1++;
        if(points[i].second==points[i+1].second)f2++;
    }
    if(f1==n-1||f2==n-1)cout<<"YES\n";
    else cout<<"NO\n";
    
    return 0;
}