#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 x_prev,y_prev;
    int flag_x=1;
    int flag_y=1;
    for(int a0 = 0; a0 < n; a0++){
        int x;
        int y;
        cin >> x >> y;
        if(a0!=0)
            {
            if(x_prev!=x)
                {
                flag_x=0;
            }
            if(y_prev!=y)
                {
                flag_y=0;
            }
        }
            x_prev=x;
            y_prev=y;
    }
    if(flag_x || flag_y)
        {
        cout<<"YES\n";
    }
    else
        {
        cout<<"NO\n";
    }
    return 0;
}