Problem:
Score : 600 points

Problem Statement

You are given a string s consisting of A, B and C.

Snuke wants to perform the following operation on s as many times as possible:

Choose a contiguous substring of s that reads ABC and replace it with BCA.

Find the maximum possible number of operations.

Constraints

1 \leq |s| \leq 200000

Each character of s is A, B and C.

Input

Input is given from Standard Input in the following format:

s

Output

Find the maximum possible number of operations.

Sample Input 1

ABCABC

Sample Output 1

3

You can perform the operations three times as follows: ABCABC → BCAABC → BCABCA → BCBCAA. This is the maximum result.

Sample Input 2

C

Sample Output 2

0

Sample Input 3

ABCACCBABCBCAABCB

Sample Output 3

6

Solution in Kotlin (1.0.0) (judge verdict: Accepted)

fun main(args: Array<String>) {
    val s = readInputLine().replace("BC", "D").toCharArray()
    
    var Acnt = 0L
    var ans = 0L

    for (i in 0 until s.size) {
        when (s[i]) {
            'A' -> Acnt++
            'D' -> ans += Acnt
            else -> Acnt = 0L
        }
    }

    println(ans)
}

fun readInputLine(): String {
    return readLine()!!
}