uses crt; 
var 
   s: string; 
   i, k: integer; 
begin 
   read(s); 
   for i := 1 to length(s) - 1 do 
   begin 
     if (s[i] = ' ') and (s[i + 1] = 'd') then 
     begin 
       k := k + 1; 
     end; 
   end; 
   write(k); 
   readln; 
   readln; 
end.