#include<stdio.h>
signed main(){
  int a,v,b,w,t;
  scanf("%d %d ",&a,&v);
  scanf("%d %d",&b,&w);
  scanf("%d",&t);
  if(v*t+a>=w*t+b){
    printf("YES\n");
  }else{
    printf("NO\n");
  }
  return(0);
}