#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 calSlope(int x1,int y1,int x2,int y2){
    if (x1-x2 == 0)
        return 0; //verticle
    else if (y1-y2 == 0)
        return 1; //h
    else
        return -1;
}

int main(){
    int n;
    cin >> n;
    
    int slope;
    int points[10][2];

    for(int a0 = 0; a0 < n; a0++){
        int x;
        int y;
        cin >> x >> y;
        points[a0][0] = x;
        points[a0][1] = y;
    }
    
    slope = calSlope(points[0][0],points[0][1],points[1][0],points[1][1]);
    bool success;
    for(int a0 = 1; a0 < n; a0++){
        int slopeT = calSlope(points[0][0],points[0][1],points[a0][0],points[a0][1]);
        if(slope >= 0 && slope != slopeT){
            success = false;
            break;
        }
        else if (slope >= 0 && slope == slopeT)
            success = true;
        else{
            success = false;
            break;
        }
    }
    
    if(success)
        cout << "YES";
    else 
        cout << "NO";
    return 0;
}