program string_8;
var s:string;
i,k:integer;
begin write('введите строку:');
readln(s);
s:=' '+s;k:=0;
for i:=1 to length(s) do
if (s[i]=' ') and (s[i+1]='b') then k:=k+1;
writeln(k);
Readln;
end.