Count Even Decimal Digits

Source: Phước Hưng OJ

Version: Phuoc Hung OJ Extended

Problem Statement

Count even decimal digits (0,2,4,6,8) of nonnegative n. Zero is an even digit, so n=0 has answer 1.

Input

One integer n.

Output

Print the count of even 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

4029

Output

3

Explanation

Digits 4,0,2 are even; 9 is odd.

Example 2

Input

0

Output

1

Explanation

The only digit is zero, which is even.