#include<bits/stdc++.h>
using namespace std;

// ----------- define -----------------------------------
#define pb push_back
#define F(i, a, b) for(i=a;i<=b;i++)
#define Fr(b, a) for(i=b;i>=a;i--)
#define pi acos(-1)
#define eps 1e-6
#define mem(a, b) memset(a, b, sizeof(a))
#define ll long long
#define ull unsinged long long
#define mp make_pair
#define ff first
#define ss second

// ---------------- typedef ------------------------------
typedef vector<int> vi;
typedef pair<int, int> pii;
typedef vector<pair<int, int> > vii;

// --------------   template ends  ------------------------

int main()
{
    //freopen("in.txt", "r", stdin);
    //freopen("out.txt", "w", stdout);
    int n, i, j, x[14], y[14];
    while(cin>>n)
    {
        F(i, 0, n-1)
        {
            cin>>x[i]>>y[i];
        }
        
        int cn=0;
        F(i, 2, n-1)
        {
            if((y[i]-y[i-1])*(x[i-1]-x[i-2]) == (y[i-1]-y[i-2])*(x[i]-x[i-1]))
                cn++;
        }
        if(cn==n-2)
            cout << "YES\n";
        else cout << "NO\n";
    }
    return 0;
}