Var
 n,Sign,Sum2:Integer;
 Num,Sum1,First,i:Byte;

Begin
 Write('n = ');
 Readln(n);
 Num:=Trunc(Ln(n)/Ln(10))+1;
 if (Num mod 2)=1 then Sign:=1 else Sign:=-1;
 Sum1:=0;
 Sum2:=0;
 for i:=1 to Num do
  begin
   First:=(n mod 10);
   Sum1:=Sum1+First;
   Sum2:=Sum2+Sign*First;
   Sign:=-Sign;
   n:=n div 10;
  end;
 Writeln('Number of digits = ',Num);
 Writeln('Sum of digits = ',Sum1);
 Writeln('First digit = ',First);
 Writeln('Alternating sum of digits = ',Sum2);
End.