codeforces#P1029A. Many Equal Substrings
Many Equal Substrings
Description
You are given a string $t$ consisting of $n$ lowercase Latin letters and an integer number $k$.
Let's define a substring of some string $s$ with indices from $l$ to $r$ as $s[l \dots r]$.
Your task is to construct such string $s$ of minimum possible length that there are exactly $k$ positions $i$ such that $s[i \dots i + n - 1] = t$. In other words, your task is to construct such string $s$ of minimum possible length that there are exactly $k$ substrings of $s$ equal to $t$.
It is guaranteed that the answer is always unique.
The first line of the input contains two integers $n$ and $k$ ($1 \le n, k \le 50$) — the length of the string $t$ and the number of substrings.
The second line of the input contains the string $t$ consisting of exactly $n$ lowercase Latin letters.
Print such string $s$ of minimum possible length that there are exactly $k$ substrings of $s$ equal to $t$.
It is guaranteed that the answer is always unique.
Input
The first line of the input contains two integers $n$ and $k$ ($1 \le n, k \le 50$) — the length of the string $t$ and the number of substrings.
The second line of the input contains the string $t$ consisting of exactly $n$ lowercase Latin letters.
Output
Print such string $s$ of minimum possible length that there are exactly $k$ substrings of $s$ equal to $t$.
It is guaranteed that the answer is always unique.
Samples
3 4
aba
ababababa
3 2
cat
catcat