var f : textfile;
    text, cuv : string;
    nrcuv, k, t, i : integer;
begin
    assign(f, 'text.in');
    reset(f);
    read(f, text);
    close(f);

    k := pos(' ', text);
    //writeln(k);
    nrcuv := 0;
    t := 0;

    while (k > 0) and (k < length(text)) do
    begin
        cuv := copy(text, 1, k-1);
        inc(nrcuv);

        for i:=1 to length(cuv) do
        begin
           if (cuv[i] in ['a'..'z']) or (cuv[i] in ['A'..'Z']) then inc(t);
        end;

        delete(text, 1, k);
        //writeln(cuv, ' ', length(cuv));
        k := pos(' ', text);
    end;

    cuv := text;
    inc(nrcuv);
    for i:=1 to length(cuv) do
        begin
           if (cuv[i] in ['a'..'z']) or (cuv[i] in ['A'..'Z']) then inc(t);
        end;
    //writeln(cuv);
    //writeln('nr de cuv ', nrcuv);
    //writeln(t);
    //writeln(t div nrcuv);

    //readln;
    assign(f, 'text.out');
    rewrite(f);
    write(f, t div nrcuv);
    close(f);
end.