# 2-тапсырма
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])
IyAyLdGC0LDQv9GB0YvRgNC80LAKCnMgPSBpbnB1dCgpLnN0cmlwKCkKayA9IGludChpbnB1dCgpKQoKYSA9IGxpc3QocykKbiA9IGxlbihhKQpmb3IgaSBpbiByYW5nZShuIC0gMSk6CiAgICBtID0gaQogICAgZm9yIGogaW4gcmFuZ2UoaSArIDEsIG4pOgogICAgICAgIGlmIGFbal0gPCBhW21dOgogICAgICAgICAgICBtID0gagogICAgYVtpXSwgYVttXSA9IGFbbV0sIGFbaV0KcHJpbnQoYVtrLTFdKQ==