A. Insert Digittime limit per test2 secondsmemory limit per test256 megabytesinputstandard inputoutputstandard outputYou have a positive number of length n and one additional digit.You can insert this digit anywhere in the number, including at the beginning or at the end.Your task is to make the result as large as possible.For example, you have the number 76543, and the additional digit is 4. Then the maximum number you can get is 765443, and it can be obtained in two ways — by inserting a digit after the 3th or after the 4th digit of the number.InputThe first line contains a single integer t (1 \le t \le 10^4) — the number of test cases.The descriptions of the test cases follow.The first line of the description of each test case contains two integers n and d (1 \le n \le 2 \cdot 10^5; 0 \le d \le 9) — the length of the number and an additional digit, respectively.The second line of the description of each test case contains a string consisting of n digits — the number that you have initially. It is guaranteed that the number does not contain leading zeros.It is guaranteed that the sum of n for all test cases does not exceed 2 \cdot 10^5.OutputFor each test case, output a string consisting of n + 1 digits — the maximum possible number that can be obtained.ExampleInput
115 4765431 012 5443 66665 6135795 89753119 498765432101234567895 7737378 1200000007 0705895912 1828127127732Output
765443
10
544
6666
613579
987531
98765443210123456789
773737
210000000
70589590
8281271277321

115 4765431 012 5443 66665 6135795 89753119 498765432101234567895 7737378 1200000007 0705895912 1828127127732
765443 10 544 6666 613579 987531 98765443210123456789 773737 210000000 70589590 8281271277321 
['greedy', 'math', 'strings', '*800']