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"

func stringToRunes(s string) (runes []rune) {
	runes = make([]rune, len(s))
	for i, r := range s {
		runes[i] = r
	}
	return
}

func main() {
	var s string
	fmt.Scan(&s)
	runes := stringToRunes(s)
	cnt := 0
	for i := 0; i < len(runes); i++ {
		if runes[i] == '1' {
			cnt++
		}
	}
	fmt.Println(cnt)
}