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: Time Limit Exceeded)

<?php
  while ($line = fgets(STDIN)) {
   $array[] = trim($line);
  }
  $count = 0;
  $n = (int)$array[0];
  $figure = explode(" ", $array[1]);
  
  for($i = 0; $i < $n; $i++) {
   $figure[$i] = (int)$figure[$i];
  }
  
  while(true) {
    $flag = false;
    for($i = 0; $i < $n; $i++) {
     if($figure[$i] % 2 != 0) $flag = true; 
    }
    
    if($flag) break;
    
    for($i = 0; $i < $n; $i++) {
     $figure[$i] /= 2; 
    }
    
    $count++;
  }
  echo($count);