var
  h,s1,v,l,k,t1,t2,x1,x2,a,b:real;
  ans,i,n:longint;
begin
  assign(input,'freefaller.in');
  assign(output,'freefaller.out');
  reset(input);rewrite(output);


  read(h,s1,v,l,k,n);
  
  ans:=0;
  t1:=sqrt(h/5);
  t2:=sqrt((h-k)/5);
  x1:=v*t2;
  x2:=v*t1;
  x1:=s1-x1+l;
  x2:=s1-x2;
  
  for i:=0 to n-1 do 
  begin
    if i-x1<=0 then a:=x1-i else a:=i-x1;
	if i-x2<=0 then b:=x2-i else b:=i-x2;
	if (a<=0.00001) or (b<=0.00001) then inc(ans);
  end;
  writeln(ans);
  close(input);close(output);
end.