Sum of Digits

Source: Phước Hưng OJ

Version: Phuoc Hung OJ Extended

Problem Statement

Given nonnegative n, calculate the sum of its decimal digits. For example, 507 has sum 12; zero has sum zero.

Input

One integer n.

Output

Print the sum of the decimal digits.

Subtasks

• Subtask 1 (20%): 0<=n<=99.
• Subtask 2 (30%): 0<=n<=10^6.
• Subtask 3 (50%): 0<=n<=10^18.

Examples

Example 1

Input

507

Output

12

Explanation

The running total is 0 -> 7 -> 7 -> 12.

Example 2

Input

0

Output

0

Explanation

The initial sum zero is already correct.