#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;

    if(n==0 || n==1)
    {
        cout << "YES";
        return 0;
    }
    double x_1,x_2,y_1,y_2;
    double eliposn = .000001;
    cin >> x_1 >> y_1 >> x_2 >> y_2;
    double x_diff = (x_1 - x_2);
    double y_diff = (y_1 - y_2);
    double m ;
    if(x_diff != 0) 
    {
        m = y_diff/x_diff;
    }
    
    for(int a0 = 0; a0 < n; a0++){
        double x;
        double y;
        double x_diff_1;
        double y_diff_1;
        cin >> x >> y;
        
        x_diff_1 = (x-x_1);
        y_diff_1 = (y-y_1);
        double m1 = y_diff_1/x_diff_1;
        if(x_diff == x_diff_1 &&  x_diff == 0)
        {
            continue;
        }

        else if( (m1 - m) < eliposn)
        {
            continue;
        }
        else
        {
            cout << "NO";
            return 0;
        }
        
    }
    cout << "YES";
    return 0;
}