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 JavaScript (node.js v5.12) (judge verdict: Runtime Error)

function main (input) {
  let count = 0;
  while(input.indexOf('ABC')>=0){
    let index = input.indexOf('ABC');
    let a = input.replace('ABC','BCA');
    count++;
    console.log(a,a.slice(index))
    input = a.slice(index);
  }
  console.log(count);
}
main(require('fs').readFileSync('/dev/stdin','utf8'));