4774: Different Subsets For All Tuples

内存限制:256 MB 时间限制:2 S 标准输入输出
题目类型:传统 评测方式:文本比较 上传者:
提交:1 通过:1

题目描述

E. Different Subsets For All Tuples
time limit per test
2 seconds
memory limit per test
256 megabytes
input
standard input
output
standard output
For a sequence a of n integers between 1 and m, inclusive, denote f(a) as the number of distinct subsequences of a (including the empty subsequence).
You are given two positive integers n and m. Let S be the set of all sequences of length n consisting of numbers from 1 to m. Compute the sum f(a) over all a in S modulo 109+7.
Input
The only line contains two integers n and m (1≤n,m≤106) − the number of elements in arrays and the upper bound for elements.
Output
Print the only integer c − the desired sum modulo 109+7.
Examples
Input
1 3
Output
6
Input
2 2
Output
14
Input
3 3
Output
174

输入样例 复制


输出样例 复制