#P1833. Different Subsets For All Tuples
Different Subsets For All Tuples
说明
E. Different Subsets For All Tuples
time limit per test
2 secondsmemory limit per test
256 megabytesinput
standard inputoutput
standard outputFor 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
样例
