【CodeForces - 1084C】The Fair Nut and String（思维，组合数学）

题干：

The Fair Nut found a string ss. The string consists of lowercase Latin letters. The Nut is a curious guy, so he wants to find the number of strictly increasing sequences p1,p2,…,pkp1,p2,…,pk, such that:

1. For each ii (1≤i≤k1≤i≤k), spi=spi= 'a'.
2. For each ii (1≤i

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

This number should be calculated modulo 109+7109+7.

Input

The first line contains the string ss (1≤|s|≤1051≤|s|≤105) consisting of lowercase Latin letters.

Output

In a single line print the answer to the problem — the number of such sequences p1,p2,…,pkp1,p2,…,pk modulo 109+7109+7.

Examples

Input

abbaa

Output

5

Input

baaaa

Output

4

Input

agaa

Output

3

Note

In the first example, there are 55 possible sequences. [1][1], [4][4], [5][5], [1,4][1,4], [1,5][1,5].

In the second example, there are 44 possible sequences. [2][2], [3][3], [4][4], [5][5].

In the third example, there are 33 possible sequences. [1][1], [3][3], [4][4].

题目大意：

   让你构造一个序列，有两个要求：1.全为‘a’字符。2.每两个a字符之间一定夹着至少一个b字符，求能构造出多少个这样的序列

解题报告：

   扫一遍遇到a就记录，遇到b就终止并开始计数 最后输出答案，就行了

AC代码：

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