output_description: Print the lexicographically smallest possible string that can be the string S
  after the K operations.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      N K
      S
attempt: U = ""
  arr = []
  lines = input().split(" ")
  N = int(lines[0])
  K = int(lines[1])
  S = input()
  T = S[::-1]
  
  for i in range(K):
      U += S
      U += T
  
  num = len(U)
  
  for j in range(num):
      if j + N <= num:
          arr.append(U[j : (j + N)])
  
  arr.sort()
  
  print(arr[0])
  
problem_description: Statement
  
  Takahashi has a string S of length N consisting of lowercase English letters.
  On this string, he will perform the following operation K times:
  
    * Let T be the string obtained by reversing S, and U be the string obtained by concatenating S and T in this order.
    * Let S' be some contiguous substring of U with length N, and replace S with S'.
  
  Among the strings that can be the string S after the K operations, find the
  lexicographically smallest possible one.
samples: [{"input": "5 1\n    bacba", "output": "aabca\n    \n\nWhen S=`bacba`, T=`abcab`, U=`bacbaabcab`, and the optimal choice of S' is\nS'=`aabca`.\n\n* * *"}, {"input": "10 2\n    bbaabbbaab", "output": "aaaabbaabb"}]