C. The Fair Nut and String
time limit per test
1 second
memory limit per test
256 megabytes
input
standard input
output
standard output

The Fair Nut found a string $s$. The string consists of lowercase Latin letters. The Nut is a curious guy, so he wants to find the number of strictly increasing sequences $p_1, p_2, \ldots, p_k$, such that:

1. For each $i$ ($1 \leq i \leq k$), $s_{p_i} =$ 'a'.
2. For each $i$ ($1 \leq i < k$), there is such $j$ that $p_i < j < p_{i + 1}$ and $s_j =$ 'b'.

The Nut is upset because he doesn't know how to find the number. Help him.

This number should be calculated modulo $10^9 + 7$.

Input

The first line contains the string $s$ ($1 \leq |s| \leq 10^5$) consisting of lowercase Latin letters.

Output

In a single line print the answer to the problem — the number of such sequences $p_1, p_2, \ldots, p_k$ modulo $10^9 + 7$.

Examples
Input
abbaa
Output
5
Input
baaaa
Output
4
Input
agaa
Output
3
Note

In the first example, there are $5$ possible sequences. $$, $$, $$, $[1, 4]$, $[1, 5]$.

In the second example, there are $4$ possible sequences. $$, $$, $$, $$.

In the third example, there are $3$ possible sequences. $$, $$, $$.