UCV2013A - Counting Ids

Little Willy just took a compilers course and is trying to implement his own compiler. First he wants to build a table with all the possible ids that a program could have. He knows that his language supports up to N different characters and any id can be up to L characters long. For example, when N = 2 (lets say characters can be 0 or 1), and L = 3, he could have the following ids: {0, 1, 00, 01, 10, 11, 000, 001, 010, 011, 100, 101, 110, 111}.

You have to write a program that can help Willy find out the size of the table. Since the answer can be really big, you must print it modulo 1000000007 (10^9+7).

Input

The input contains several test cases. Each test case will consist of a single line containing two integers N and L. N is the number of characters that can be part of an id and L is maximum length supported by the language (1 <= N <= 65535, 1 <= L <= 10^5).

End of the input is indicated by a test case with N = 0, L = 0 that should not be processed.

Output

For each test case output a single line containing the number of possible ids modulo 10^9+7.

Example

Input:
2 3
128 32
0 0 Output: 14
792805767

Added by:Hector Navarro
Date:2013-07-22
Time limit:1s
Source limit:50000B
Memory limit:1536MB
Cluster: Cube (Intel G860)
Languages:All except: ASM64
Resource:Local UCV 2013. Héctor Navarro

hide comments
2014-06-17 12:46:00 Amitayush Thakur
Weak test cases. Doesn't have a test case where N=1.
2014-01-05 20:53:42 যোবায়ের
Your input file should contain some cases where N = 1. Just saying...

Last edit: 2014-01-05 20:54:08
2013-09-13 08:06:40 Himanshu
@bigBOSS
not a beginner problem
learn a lot form this problem....

Last edit: 2013-09-13 08:15:34
2013-08-02 01:19:28 Miguel Oliveira
@Degree of Freedom check http://en.wikipedia.org/wiki/Extended_Euclidean_algorithm it explains the modular inverse
2013-08-01 18:16:14 Hitman
To my surprise O(L) works fine

Last edit: 2013-08-01 18:16:38
2013-08-01 06:48:39 Ouditchya Sinha
Easy but certainly not a tutorial problem, increased constraints could make it more challenging. :)
2013-07-31 16:15:31 narendray
Miguel Oliveira : Any link of Modular inverse regarding the algo.
2013-07-30 14:16:44 Anubhav Balodhi
What da?!? same code nzec in Python 3.2.3 but ac in python 2.7...
2013-07-29 13:51:09 abdelkarim
simple but nice math one ;) .
2013-07-29 13:22:57 mystique_blue
Akash your comment is a spoiler. Please remove it. Discuss in the forum.
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