program cogs102;
const
   mm=0.00001;
   g=10;
var
  ans,i,j,n,m:longint;
  h,s1,v,k,l,t1,t2:extended;
  h1,h2:extended;
begin
   assign(input,'freefaller.in'); reset(input);
   assign(output,'freefaller.out'); rewrite(output);
    readln(h,s1,v,l,k,n);
    ans:=0;
    for i:=n-1 downto 0 do
     begin
        t1:=(s1-i-mm) /v;
        t2:=(s1-i+mm+l)/v;
        h1:=h-(g*t1*t1/2)-mm;
        h2:=h-(g*t2*t2/2)-mm;
        if (h1>=0) then
         begin
           if (h1<=k)or (h2<=k) then inc(ans);
         end;

     end;
    writeln(ans);

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