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 PHP (7.4.4) (judge verdict: Accepted)

<?php

$result = 0;
$s = trim(fgets(STDIN));
$s = str_replace(array("\r\n","\r","\n"), '', $s);
$s = str_split($s);

for ($i=0; $i<3; $i++) {
    if ($s[$i] != 0) {
        $result++;
    }
}

echo $result;