program cojs102;
var
  t,h,s1,v,l,k:extended;
  i,ans,n:longint;

function pan(i:longint):boolean;
var
  h1,h2,t1,t2:extended;
begin
  t1:=(s1-i)/v;
  t2:=(s1-i+l)/v;
  h1:=h-5*sqr(t1);
  h2:=h-5*sqr(t2);
  if (h1<=k+0.00001)and(h1>=-0.00001) then exit(true);
  if (h1>=k+0.00001)and(h2<=k+0.00001) then exit(true);
  exit(false);
end;

begin
assign(input,'freefaller.in');reset(input);
assign(output,'freefaller.out');rewrite(output);

  readln(h,s1,v,l,k,n);
  for i:=n-1 downto 0 do
  if pan(i) then inc(ans);
  writeln(ans);

close(input);close(output);
end.