#include<stdio.h>
int main(){
int A,B,V,W,T;
int A1,B1;
  scanf("%d %d",&A,&V);
  scanf("%d %d",&B,&W);
  scanf("%d",&T);
  A1=A+V*T;
  B1=B+W*T;
  if(A1>=B1)printf("YES");
  else printf("NO");
return 0;
}