#include <stdio.h>

int main(void)
{
  int A = 0, B = 0, V = 0, W = 0, T = 0;
  scanf("%d %d\n", &A, &V);
  scanf("%d %d\n", &B, &W);
  scanf("%d\n", &T);
  
  if ( (A + V * T) <= (B + W * T) ) {
    printf("YES\n");
  }
  else {
    printf("NO\n");
  }
}