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
function getArrayFromStdin() {
	$line = trim(fgets(STDIN));
	$line = str_replace(array("\r\n","\r","\n"), '', $line);
	$line = explode(" ", $line);
	return $line;
}

$n = trim(fgets(STDIN));
$numbers = getArrayFromStdin();

$count = 0;
while(true) {
  $flg = true;
  for ($i = 0; $i < $n; $i++) {
    if ($numbers[$i] % 2) {
      $flg = false;
      break;
    } else {
      $numbers[$i] /= 2; 
    }
  }
  
  if ($flg) {
    $count += 1;
  } else {
    break;
  }
}

echo $count;