/* -*- coding: utf-8 -*-
 *
 * 3511.cc:  No.3511 Skg - yukicoder
 */

#include<cstdio>
#include<algorithm>

using namespace std;

/* main */

int main() {
  int a, b, c, d, s;
  scanf("%d%d%d%d%d", &a, &b, &c, &d, &s);

  if (a * c + b * d <= s) puts("Yes");
  else puts("No");

  return 0;
}