You are given a string $S$ of length $N$. The string contains only '$a$', '$b$', and '$c$'.

Your task is to find the count of substrings in string $S$ that have $F('a') \gt F('c')$. Print $ans \% (10^{9}+7)$.

Here, $F(x)$ denotes the frequency of occurrence of character $x$ in the string.

Input format

• The first line contains an integer $N$ that denotes the length of the string.
• The next line contains string $S$.

Output format

Print the count of substrings in string $S$ that have $F('a') \gt F('c')$ modulus $10^9 + 7$. 

Constraints
$1 \le N \le 10^ 5$