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.

Input

Input is given from Standard Input in the following format:
s_{1}s_{2}s_{3}

Output

Print the answer.

Constraints

• Each of s_1, s_2 and s_3 is either 1 or 0.

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.

见题面 Input 部分

见题面 Output 部分