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

void solve(){
    int a, b, c, d, s;
    cin >> a >> b >> c >> d >> s;
    if(a * c + b * d <= s){
        cout << "YES" << endl;
        return;
    } else{
        cout << "NO" << endl;
        return;
    }
}

int main(){
    solve();
    return 0;
}