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 (5.6.30) (judge verdict: Wrong Answer)

$a = array(0, 1); 
$b = array(0, 1);
$c = array(0, 1);

foreach ($a as $val1) {
    foreach ($b as $val2) {
        foreach ($c as $val3) {
            if($val1 === 1 || $val2 === 1 || $val3 ===1) {
              echo( $val1 + $val2 + $val3);
            }
            echo ("[$val1, $val2, $val3]");
        }
    }
}