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A8437. Quantity of Strings

编程题 普及/提高-

题目描述

Just in case somebody missed it: this winter is totally cold in Nvodsk! It is so cold that one gets funny thoughts. For example, let's say there are strings with the length exactly $n$ , based on the alphabet of size $m$ . Any its substring with length equal to $k$ is a palindrome. How many such strings exist? Your task is to find their quantity modulo $1000000007$ ( $10^{9}+7$ ). Be careful and don't miss a string or two!

Let us remind you that a string is a palindrome if it can be read the same way in either direction, from the left to the right and from the right to the left.

输入格式

The first and only line contains three integers: $n$ , $m$ and $k$ ( $1<=n,m,k<=2000$ ).

输出格式

Print a single integer — the number of strings of the described type modulo $1000000007$ ( $10^{9}+7$ ).

输入输出样例

输入 #1
1 1 1
输出 #1
1
输入 #2
5 2 4
输出 #2
2

说明/提示

In the first sample only one string is valid: "a" (let's denote the only letter of our alphabet as "a").

In the second sample (if we denote the alphabet letters as "a" and "b") the following strings are valid: "aaaaa" and "bbbbb".
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