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: Wrong Answer)

fun main(args : Array<String>) {
    val ss = readLine()!!

    var aCnt = 0
    var bFound = false
    var ans = 0
    ss.forEach {
        if (it == 'A') {
            aCnt++
            return@forEach
        }

        if (it == 'B' && aCnt > 0) {
            bFound = true
            return@forEach
        }

        if (it == 'C' && bFound) {
            ans += aCnt
            bFound = false
            return@forEach
        }

        aCnt = 0
    }

    println(ans)
}