# #CSPJ2019A. 数字游戏 (Number Games)

# 数字游戏 (Number Games)

## Description

Little K sent a binary string of length $8$ to Little P to play a number game. Little P wants to know how many times the character $1$ occurs in the string.

Note: A binary string is a string in which each character is either $0$ or $1$. E.g., "`101`

" (withuot quotes) is a binary string of length $3$.

## Input Format

The input has only one line consisting of a binary string $s$ of length $8$.

## Output Format

Print the number of times the character $1$ occurs in $s$.

```
00010100
```

```
2
```

## Constraints

For $20\%$ of the data, all characters in the string are $0$s.

For $100\%$ of the data, the input may contain both $0$s and $1$s. The length of the string is $8$.