Sum of Digits

Given an integer n, compute the sum of its digits by considering its absolute value. In other words, let \(n\) be an integer, then let \(|n|\) be its absolute value. If \(|n|\) is expressed with digits \(d_1, d_2, \dots, d_k\), the digit sum \(S\) is given by:

$$S = \sum_{i=1}^{k} d_i$$

If the input cannot be interpreted as an integer, output None.

Examples:

• Input: 123, Output: 6
• Input: -123, Output: 6
• Input: abc, Output: None

inputFormat

A single line containing a string. The program should interpret the input as an integer.

outputFormat

Print the sum of the digits of the absolute value of the integer. If the input is not a valid integer, print "None".## sample

123

6