You are given a string S of length N. Among its subsequences, count the ones such that all characters are different, modulo 109+7. Two subsequences are considered different if their characters come from different positions in the string, even if they are the same as strings.
Here, a subsequence of a string is a concatenation of one or more characters from the string without changing the order.
·S consists of lowercase English letters.
Input is given from Standard Input in the following format:
Print the number of the subsequences such that all characters are different, modulo 109+7.