hexa2dec = {
'0': 0,
'1': 1,
'2': 2,
'3': 3,
'4': 4,
'5': 5,
'6': 6,
'7': 7,
'8': 8,
'9': 9,
'A': 10,
'B': 11,
'C': 12,
'D': 13,
'E': 14,
'F': 15,
}
T = int(input())
for tc in range(1, T+1):
N, K = map(int, input().split())
numbers = list(input())
candidates = set()
len_number = N//4
for i in range(len_number):
for each_num in range(0, N, len_number):
candidates.add(''.join(numbers[each_num:each_num+len_number]))
last_elem = numbers.pop()
numbers = [last_elem] + numbers
dec_candidates = []
for elem in candidates:
dec_cand = 0
for i in range(len_number):
dec_cand += hexa2dec[elem[len_number - 1 - i]]*(16**i)
dec_candidates.append(dec_cand)
dec_candidates.sort(reverse=True)
print(f'#{tc} {dec_candidates[K-1]}')