Monk loves to play games. On his birthday, his friend gifted him a string S. Monk and his friend started playing a new game called as Suffix Game. In Suffix Game, Monk's friend will ask him lexicographically $k^{th}$ smallest suffix of the string S. Monk wants to eat the cake first so he asked you to play the game.

Video approach to solve this question: here

Input Format:
First line contains a string S ($1 \le |S| \le 25$) and an integer k ($1 \le k \le |S|$).

Output Format:
Print the lexicographically $k^{th}$ smallest suffix of the string S.

Note:
Those who are not familiar with suffix and lexicographical order, can read about it from https://en.wikipedia.org/wiki/Suffix and https://en.wikipedia.org/wiki/Lexicographical_order.