#include <bits/stdc++.h>
using namespace std;
template<typename T,typename T1>T amax(T &a,T1 b){if(b>a)a=b;return a;}
template<typename T,typename T1>T amin(T &a,T1 b){if(b<a)a=b;return a;}
// =================
#define f(i, k, n) for (int i = k; i < n; i++)
#define ll long long
#define pb push_back
#define fr first
#define sc second
#define len(s) s.size()
#define all(v) v.begin(), v.end()
// =================

const int mod = 1e9+7;
const int N = 3e5 + 1;

void solve()
{
    int v,t,s,d;
    cin>>v>>t>>s>>d;
    puts( (d>s*v || d<v*t) ? "Yes" : "No");
}

signed main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);

    int t=1;
    // cin>>t;
    while (t--)
        solve();
    return 0;
}
#include <iostream>
#include <cmath>

using namespace std;

int main(){
    int N, a, b;
    
    cin >> N;
    int arr[N], arr1[N];
    for(int i = 0; i < N; i++){
        cin >> a;
        arr[i] = a;
    }
    for(int k = 0; k < N; k++){
        cin >> b;
        arr1[k] = b;
    }
    int result = 0;

    for(int j = 0; j < N; j++){
        result += arr[j]*arr1[j];
    }
    if(result == 0){
        cout << "Yes" << endl;}
    else{
        cout << "No" << endl;
    }
}