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 PHP7 (7.0.15) (judge verdict: Time Limit Exceeded)

<?php
  $n = fgets(STDIN);
  $numbers = explode(' ',fgets(STDIN));
  $a = 0;  
  $continue = true;
  while ($continue) {
    foreach ($numbers as $number) {
    	if($number%2 != 0) {
        	$continue = false;
          	break;
        } else {
        	$number = $number/2;
        }
    }
  $a++;
  }
  echo $a;

  ?>