#include <bits/stdc++.h>

int main() {
	int a, b, c, d, x;
	std::cin >> a >> b >> c >> d >> x;
	if ((a*c)+(b*d) > x) {
		std::cout << "No" << std::endl;
	}
	else {
		std::cout << "Yes" << std::endl;
	}
}