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 C++14 (GCC 5.4.1) (judge verdict: Accepted)

#include <bits/stdc++.h>
using namespace std;

main(){
  int a,b,c,d,e,f;
  cin>>a;
  b=a/100;
  c=a-b*100;
  d=c/10;
  e=c-d*10;
  f=b+d+e;
  cout<<f<<endl;
}