24 task letters_range

begin
    var f: text;
    var a: string; //AGADFGADFGT
    var b: char;
    var col_g: integer;
    Reset(f, 'D:/inf_26_04_21_24.txt');
    var max_range : integer;
    while not eof(f) do
    begin
        readln(f, a);
        var l_range: array['A'..'Z'] of integer;
        col_g := a.CountOf('G');
        if col_g < 25 then begin
            begin
                for var i := 'A' to 'Z' do
                begin
                  l_range[i] := a.LastIndexOf(i) - a.IndexOf(i);
                end;

                if max_range < l_range.max() then
                  max_range := l_range.max();
            end;
        end;
    end;
    print(max_range);
end.