5791：Two

Alice gets two sequences A and B. A easy problem comes. How many pair of sequence A' and sequence B' are same. For example, {1,2} and {1,2} are same. {1,2,4} and {1,4,2} are not same. A' is a subsequence of A. B' is a subsequence of B. The subsequnce can be not continuous. For example, {1,1,2} has 7 subsequences {1},{1},{2},{1,1},{1,2},{1,2},{1,1,2}. The answer can be very large. Output the answer mod 1000000007.

The input contains multiple test cases.

For each test case, the first line cantains two integers $N, M(1\leq N,M\leq 1000)$. The next line contains N integers. The next line followed M integers. All integers are between 1 and 1000.

For each test case, output the answer mod 1000000007.