var
s:string;
i,k:integer;
begin
readln(s);
s:=' '+s;
for i:=1 to length(s) do
if copy(s,i,2)=' b' then inc(k);
writeln(k);
end.
var
s:string;
i,k:integer;
begin
readln(s);
s:=' '+s;
for i:=1 to length(s) do
if copy(s,i,2)=' b' then inc(k);
writeln(k);
end.