program cojs102;
const
  g=10;
var
  h,s1,v,l,k:extended;
  sv1,sv2,t1,t2:extended;
  i,j,m,n,ans:longint;
  ll,rr:longint;
function min(a,b:longint):longint;
begin
  if a>b then exit(b)
  else
    exit(a);
end;
begin
  assign(input,'freefaller.in');
  assign(output,'freefaller.out');
  reset(input);
  rewrite(output);
 
  readln(h,s1,v,l,k,n);
  if h=k then k:=k-0.00002;
  t1:=sqrt(2*(h-k-0.00001)/g);
  t2:=sqrt(2*(h+0.00001)/g);
  sv1:=v*t1;
  sv1:=s1-sv1;
  sv1:=sv1+0.00001+l;
  rr:=trunc(sv1);
  rr:=min(rr,n-1);
  sv2:=v*t2;
  sv2:=s1-sv2;
  sv2:=sv2-0.00001;
  ll:=trunc(sv2)+1;
  if ll>n-1 then
    begin
	  writeln(0);
	  close(input);
	  close(output);
	  halt;
	end;
  ans:=rr-ll+1;
  if ans>n then
    ans:=n;
  writeln(ans);
 
  close(input);
  close(output);
end.