#include<bits/stdc++.h>
using namespace std;
typedef long long ll; 
typedef unsigned long long ull;
typedef pair<int,int> pii;
typedef vector<int> vec; 
typedef vector<ll> vecl; 
const int INF   = 1000000001;
const ll  INFL  = 1000000000000000001;
#define loop(i,a,b) for(i=a;i<b;i++)
#define fill(a,i) memset(a,i,sizeof(a))
#define M 1000000007
#define pb push_back
#define popb pop_back
#define pf push_front
#define mp make_pair
#define fi first
#define sec second
#define debug(x) cout << '>' << #x << '=' << x << endl;
#define sz(x) ((int)x.size())
#define si(n) scanf("%d",&n)
#define gi(n) printf("%d\n",n)
#define sl(n) scanf("%I64d",&n)
#define gl(n) printf(" %I64d\n",n)
#define sll(n) scanf("%lld",&n)
#define gll(n) printf("%lld\n",n)
#define nl() printf("\n")
#define limit 1000009
#define pi 3.14159
#define fread freopen("abc.txt","r",stdin)
#define fwrite freopen("out.txt","w",stdout);

int a[100];
int b[100];

int main(){
    int n;
    cin >> n;
    for(int a0 = 0; a0 < n; a0++){
        int x;
        int y;
        cin >> x >> y;
        a[a0]=x;
        b[a0]=y;
        
    }
    int flag=0;
    int i=0;
    for(i=0;i<=n-2;i++)
        {
           
           float  x = (float) (b[i+1]-b[i]) /(a[i+1]-a[i]) ;
           float  y = (float) (b[i+2]-b[i+1]) /(a[i+2]-a[i+1]) ;
        
         if(x!=y)
             {
             flag=1;
         }
           
           
    }
    
    if(flag)
        cout<<"NO\n";
    else
        cout<<"YES\n";
    return 0;
}