#include <stdio.h>

int main()
{
  char buf1[4];
  char buf2[4];
  char buf3[4];
  int A, V, B, W, T;
  
  fgets(buf1, 4, stdin);
  fgets(buf2, 4, stdin);
  fgets(buf3, 4, stdin);
  
  A = buf1[0] - '0';
  V = buf1[2] - '0';
  B = buf2[0] - '0';
  W = buf2[2] - '0';
  T = buf3[0] - '0';
  
  if(A + V * T >= B + W * T) printf("YES\n");
  else printf("NO\n");
  
  return 0;
}