Multiply Big Numbers

a and b are non-negative whole numbers written as strings of decimal digits (no leading zeros, except the number zero itself). Return their product as a string.

The numbers can have thousands of digits, far beyond a 64-bit integer.

Examples

Example 1

Input:

multiply_strings('123', '456')

Output:

'56088'

Example 2

Input:

multiply_strings('0', '99999')

Output:

'0'

Constraints

• 1 <= len(a), len(b) <= 20000
• Digits only, no leading zeros except for "0".