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
	$n = fgets(STDIN);
	$a = explode(" ",fgets(STDIN));
	for($i=0;$i < $n;$i++){
    	$a[$i] = intval($a[$i]);
    }
$ans = 0;
$endflag = false;
while(true){
	for($i=0;$i < $n;$i++){
    	if($a[$i] % 2 == 0){
        	$a[$i] /= 2;
        }else{
          	$endflag = true;
        }
    }
  if($endflag)break; 
  $ans++;
}
 
echo $ans;
?>