Score : $100$ points

Problem Statement

Snuke prepared $6$ problems for a upcoming programming contest. For each of those problems, Rng judged whether it can be used in the contest or not.

You are given a string $S$ of length $6$. If the $i$-th character of $s$ is 1, it means that the $i$-th problem prepared by Snuke is accepted to be used; 0 means that the problem is not accepted.

How many problems prepared by Snuke are accepted to be used in the contest?

Constraints

• The length of $S$ is $6$.
• $S$ consists of 0 and 1.

Inputs

Input is given from Standard Input in the following format:

$S$

Outputs

Print the number of problems prepared by Snuke that are accepted to be used in the contest.

111100

4

The first, second, third and fourth problems are accepted, for a total of four.

001001

2

000000

0