Problem:
Score : 100 points

Problem Statement

Snuke has a grid consisting of three squares numbered 1, 2 and 3.
In each square, either 0 or 1 is written. The number written in Square i is s_i.

Snuke will place a marble on each square that says 1.
Find the number of squares on which Snuke will place a marble.

Constraints

Each of s_1, s_2 and s_3 is either 1 or 0.

Input

Input is given from Standard Input in the following format:

s_{1}s_{2}s_{3}

Output

Print the answer.

Sample Input 1

101

Sample Output 1

2

A marble will be placed on Square 1 and 3.

Sample Input 2

000

Sample Output 2

0

No marble will be placed on any square.

Solution in OCaml (4.02.3) (judge verdict: Accepted)

(* --------------Encoder-------------- *)
(* -----function----- *)
(*
let encoder = 0
*)

(* -------test------- *)
(* ----------------------------------- *)

(* --------------Decoder-------------- *)
(* -----function----- *)
(*
let decoder ans = ""
*)

(* -------test------- *)
(* ----------------------------------- *)

(* --------------Processor-------------- *)
(* -----function----- *)
(*
let processor dat = 0
*)

(* -------test------- *)
(* ----------------------------------- *)


(* ----------------main---------------- *)
(*
let () = print_endline (decoder (processor encoder))
*)
(* ------------------------------------ *)
let rec f lst = 
        match lst with
                [] -> 0
                | first :: rest -> 
                                let frest = f rest in
                                if first = 1 then
                                        1 + frest
                                else
                                        frest
        
let () = Scanf.scanf "%1d %1d %1d" (fun a b c -> f [a; b; c])
|> Printf.printf "%d\n"