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CSES Problem Set

String Removals


Task | Statistics


CSES - String Removals

Time limit:1.00 s Memory limit:512 MB

You are given a string. You can remove any number of characters from it, but you cannot change the order of the remaining characters.

How many different strings can you generate?

Input

The first input line contains a string of size $n$. Each character is one of a–z.

Output

Print one integer: the number of strings modulo $10^9+7$.

Constraints
Example

Input:
aybabtu

Output:
103