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 Go (1.6) (judge verdict: Accepted)

package main

import (
	"fmt"
	"io"
	"os"
)

var (
	reader io.Reader = os.Stdin
	writer io.Writer = os.Stdout
)

func main() {
	run()
}

func run() {
	var str string
	fmt.Fscan(reader, &str)
	var count int

	for _, r := range str {
		if r == '1' {
			count++
		}
	}

	fmt.Fprintln(writer, count)
}