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 JavaScript (node.js v5.12) (judge verdict: Runtime Error)

function main(input) {
  const nums=input.split("");
  // nums=["1","0","0"];
  let sum=0;
  for(let i=0;i<=2;i++){
   if(nums[i]=="1")sum++; 
  }
  console.log(sum);
}
main(require('fs').readFileSync('/dev/stdin', 'utf8'));