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

#define rep(i, a, b) for (int i = a; i < b; i++)
using ll = long long;

int main(){
	ll a, b, c, d, s;
	cin >> a >> b >> c >> d >> s;
	string ans = "No";
	if(a * c + b * d <= s) ans = "Yes";
	cout << ans << endl;
}