program pku2509(input, output);

VAR sum, n, k: longint;

BEGIN
  while not eof do
    begin
      read(n, k);
      sum:=n;
      
      while n>=k do
        begin
          sum:=sum+ (n DIV k);
          n:= (n MOD k) + (n DIV k) ;
        end;
      writeln(sum);
    end;
END.