{$mode objfpc}
uses math;

var
  i,n,kq:integer;
  o:char;
  f1,f2,f3,f4:boolean;

begin
  readln(n);
  for i:=1 to n do
    begin
      read(o);
      if ('0' <= o) and (o <= '9') then f1:=true
      else
      if ('a' <= o) and (o <= 'z') then f2:=true
      else
      if ('A' <= o) and (o <= 'Z') then f3:=true
      else
      f4:=true;
    end;
  if not f1 then inc(kq);
  if not f2 then inc(kq);
  if not f3 then inc(kq);
  if not f4 then inc(kq);
  write(max(kq , 6-n));
end.