#include <iostream>
#include <fstream>
#include <vector>
#include <cmath>
#include <ctime>
#include <sstream>
#include <algorithm>
#include <set>
#include <map>
#include <unordered_map>
#include <unordered_set>

using namespace std;

struct Point {
    int x, y;
};

int main()
{
    ifstream fin;
    fin.open("input.txt");
    size_t N;
    fin >> N;
    vector<Point> points(N);
    for (size_t i = 0; i < N; i++)
        fin >> points[i].x >> points[i].y;
    fin.close();

    bool IsOneLine = true;
    for (size_t i = 2; i < N; ++i)
        if (0.5 * ((points[i - 2].x - points[i].x) * (points[i - 1].y - points[i].y) -
                   (points[i - 1].x - points[i].x) * (points[i - 2].y - points[i].y)) != 0) {
            IsOneLine = false;
            break;
        }
    fstream fout;
    fout.open("output.txt", ios::out);

    if (IsOneLine)
        fout << "yes";
    else
        fout << "no";
    fout.close();

    return 0;
}