Counting a^i b^j c^k subsequences

You are given a string $S$ built from the letters a, b, and c only. Count the subsequences of $S$ that have the form $a^i b^j c^k$, where $i \ge 1$, $j \ge 1$, and $k \ge 1$.

$a^i b^j c^k$ is the string with $i$ copies of a, then $j$ copies of b, then $k$ copies of c. For example, $a^2 b^3 c^1$ is aabbbc and $a^3 b^1 c^6$ is aaabcccccc.

A subsequence is what remains after deleting zero or more characters of $S$ and keeping the rest in their original order. Two subsequences that use different sets of positions count separately, even when the remaining strings are equal.

The first line contains the string $S$, built from the letters a, b, and c only. The length of $S$ is at most 1,000,000.

On the first line, print the number of subsequences of $S$ of the form $a^i b^j c^k$, modulo 1,000,000,007.