#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef string str;
int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    ll a, b, c, d, k;
    cin >> a >> b >> c >> d >> k;
    if (a * c + b * d <= k) cout << "Yes\n";
    else cout << "No\n";
    return 0;
}