N. Number Reductiontime limit per test2 secondsmemory limit per test512 megabytesinputstandard inputoutputstandard outputYou are given a positive integer x.You can apply the following operation to the number: remove one occurrence of any digit in such a way that the resulting number does not contain any leading zeroes and is still a positive integer. For example, 10142 can be converted to 1142, 1042, 1012 or 1014 (note that 0142 is not a valid outcome); 10 can be converted to 1 (but not to 0 since it is not positive).Your task is to find the minimum positive integer that you can obtain from x if you can apply the aforementioned operation exactly k times.InputThe first line contains a single integer t (1 \le t \le 10^5) — the number of test cases.The first line of each test case contains a single integer x (1 \le x < 10^{500000}).The second line contains a single integer k (0 \le k < |x|), where |x| is the length of the number x.The sum of |x| over all test cases does not exceed 5 \cdot 10^5.OutputFor each test case, print one integer — the minimum positive number that you can obtain from x if you can apply the operation exactly k times.ExampleInput
510000413370987654321666837494128578086523Output
1
1337
321
344128
7052

510000413370987654321666837494128578086523
1 1337 321 344128 7052 
['greedy', '*1500']