program goat;
  const
    max                         =300000;
  var
    s,p                         :longint;
    f                           :array[-20..max,-10..120] of longint;
    f1,f2                       :text;
  procedure init;
  begin
    assign(f1,'goat.in');
    reset(f1);
    assign(f2,'goat.out');
    rewrite(f2);
    readln(f1,s,p);
    filldword(f,sizeof(f) div 4,1000000000);
    f[0,0]:=0;
  end;
  function xiao(x,y:longint):longint;
  begin
    xiao:=maxlongint;
    if x<xiao then
      xiao:=x;
    if y<xiao then
      xiao:=y;
  end;
  procedure main;
    var
      i,j                       :longint;
      min,ge                    :longint;
  begin
    for i:=1 to s do
      begin
        for j:=1 to p do
          begin
            min:=maxlongint;
            if j=p-10 then
              begin
                ge:=xiao(f[i-1,j+1]+1,xiao(f[i-5,j-2]+1,xiao(f[i-10,j-5]+1,f[i-10,j]+10)));
                if ge<min then
                  min:=ge;
              end
            else
              begin
                ge:=xiao(f[i-1,j+1]+1,xiao(f[i-5,j-2]+1,f[i-10,j-5]+1));
                if ge<min then
                  min:=ge;
              end;
            f[i,j]:=min;
          end;

      end;
  end;
  procedure print;
  begin
    writeln(f2,f[s,p]);
    close(f1);
    close(f2);
  end;
  begin
    init;
    main;
    print;
  end.