Write a program to compute the sum of two positive integers.
Each integer may contain up to n digits, where 0<n≤18.
Because the integers can be very large, an appropriate data type should be used to correctly perform the addition.
Two positive integers a and b, each with at most 18 digits.
One integer representing the sum of a and b.
Ensure that the output, including formatting 輸出格式, exactly matches the provided samples.