Adding Large Numbers

This problem requires you to implement a function that computes the sum of two large non-negative integers, which are provided as strings. The integers can be extremely large and may not fit in standard integer data types. Your task is to simulate the addition process or use language-specific big integer implementations to correctly perform the addition.

The input will consist of a number of test cases. For each test case, you are given two strings representing large non-negative integers. Your program should output the sum of these two numbers as a string.

It is guaranteed that the input strings will only contain digits 0–9 with no leading zeros (except for the number zero itself).

inputFormat

The first line of the input contains a single integer T denoting the number of test cases. Each of the following T lines contains two non-negative integers separated by a space, where each integer is given as a string. (For example: 1234 5678.)

outputFormat

For each test case, output a single line containing the sum of the two input numbers, represented as a string.## sample

2
1234 5678
9999999999999999 1

6912
10000000000000000