program bly(input,output);
var
  f:array[1..3,1..2] of integer;
  s,p:longint;
  min:int64;
  i,j:integer;
  f1,f2:text;

  procedure dg(time,long,pl:longint);
  var
    i0:longint;
  begin
    if long>=s then begin if time<min then min:=time; end;
    if long<s then  begin
      if pl>=p then dg(time+10,long+10,pl-10)
        else begin
          for i0:=1 to 3 do begin
            if (pl+f[i0,2]<=p)and(pl+f[i0,2]>=0) then
              dg(time+1,long+f[i0,1],pl+f[i0,2]);
          end;
        end;
    end;
  end;


begin
  min:=maxint;
  f[1,1]:=1; f[1,2]:=-1;
  f[2,1]:=5; f[2,2]:=2;
  f[3,1]:=10; f[3,2]:=5;
  assign(f1,'goat.in');
  reset(f1);
  readln(f1,s,p);
  close(f1);

  dg(0,0,0);

  assign(f2,'goat.out');
  rewrite(f2);
  writeln(f2,min);
  close(f2);
end.