s = input().strip()
k = int(input())
a = list(s)
n = len(a)
for i in range(n - 1):
m = i
for j in range(i + 1, n):
if a[j] < a[m]:
m = j
a[i], a[m] = a[m], a[i]
print(a[k-1])
cyA9IGlucHV0KCkuc3RyaXAoKQprID0gaW50KGlucHV0KCkpCmEgPSBsaXN0KHMpCm4gPSBsZW4oYSkKZm9yIGkgaW4gcmFuZ2UobiAtIDEpOgogICAgbSA9IGkKICAgIGZvciBqIGluIHJhbmdlKGkgKyAxLCBuKToKICAgICAgICBpZiBhW2pdIDwgYVttXToKICAgICAgICAgICAgbSA9IGoKICAgIGFbaV0sIGFbbV0gPSBhW21dLCBhW2ldCnByaW50KGFbay0xXSk=