#include <stdio.h>

int main(void)
{
  int A = 0;
  int B = 0;
  int V = 0;
  int W = 0;
  int T = 0;

  scanf("%d %d", &A, &V);
  scanf("%d %d", &B, &W);
  scanf("%d", &T);
  
  if ( (A + V * T) >= (B + V * T) ) {
    printf("YES");
  }
  else {
    printf("NO");
  }
  return 0;
}