str = input()
a = str.split(" ")
n = (int)(a[0])
k = (int)(a[1])
str = input();
for ii in range(k-1):
  s = str + str[::-1]
  s1 = s[0:n]
  for i in range(1,n+1):
    s2 = s[i:n+i]
    if(s1>s2):
      s1 = s2
  str = s1[::-1]

s = str + str[::-1]
s1 = s[0:n]
for i in range(1,n+1):
  s2 = s[i:n+i]
  if(s1>s2):
    s1 = s2
print(s1)