Number of distinct substrings

You are given a string $S$. Write a program that counts how many distinct substrings $S$ has.

A substring is a contiguous piece cut out of $S$, and its length must be at least 1.

For example, the substrings of ababc are a, b, a, b, c, ab, ba, ab, bc, aba, bab, abc, abab, babc, ababc, and 12 of them are distinct.

The first line contains the string $S$. $S$ consists of lowercase letters only, and its length is at most 1,000.

Print the number of distinct substrings of $S$ on the first line.