program one;
var a,numbers,lower_case,upper_case,special_characters:string;
    n,i,dksum,dknum,dklow,dkup,dksp: integer;

function number(x:char):boolean;
var i:longint;
begin
    number:=false;
    for i:=1 to length(numbers) do
        if x=numbers[i] then 
            begin
                 number:=true;
                 break;
            end;
end;

function lowcase(x:char):boolean;
var i:longint;
begin
    lowcase:=false;
    for i:=1 to length(lower_case) do
        if x=lower_case[i] then 
            begin
                 lowcase:=true;
                 break;
            end;
end;

function uppcase(x:char):boolean;
var i:longint;
begin
    uppcase:=false;
    for i:=1 to length(upper_case) do
        if x=upper_case[i] then 
            begin
                 uppcase:=true;
                 break;
            end;
end;

function sp(x:char):boolean;
var i:longint;
begin
    sp:=false;
    for i:=1 to length(special_characters) do
        if x=special_characters[i] then 
            begin
                 sp:=true;
                 break;
            end;
end;

begin
    a:='test';
    readln(input,n);
    readln(input,a);
    numbers:='0123456789';
    lower_case:='abcdefghijklmnopqrstuvwxyz';
    upper_case:='ABCDEFGHIJKLMNOPQRSTUVWXYZ';
    special_characters:='!@#$%^&*()-+';
    dknum:=0;
    dklow:=0;
    dkup:=0;
    dksp:=0;
    for i:=1 to n do
        begin
            if number(a[i])=true then dknum:=1;
            if lowcase(a[i])=true then dklow:=1;
            if uppcase(a[i])=true then dkup:=1;
            if sp(a[i])=true then dksp:=1;
        end;
    dksum:=dknum+dklow+dkup+dksp;
    if (n<6) and (dksum<=4) then 
        if (6-n)<(4-dksum) then write(4-dksum) else write(6-n);
    if (n>=6) and (dksum<4) then write(4-dksum);
    if (n>=6) and (dksum=4) then write(0);
end.