n, k = map(int, input().split())
s = str(input())

u = s + s[::-1]
ss = s

times = min(n, k)
for i in range(times):
    for j in range(n):
        part = u[j:j+n]
        if u[j:j+n] < ss:
            ss = part
    s = ss
    u = s[::-1] + s

print(s)