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: Time Limit Exceeded)

var main = standardInput => {
  var s = standardInput;
  var count = 0;

  while (s.indexOf("ABC") !== -1) {
    var i = s.indexOf("ABC");
    var before = s.substr(0,i)
    var after = s.substr(i+3) || ""
    s = before + "BCA" + after;
    count += 1;
    // console.log(s)
  }
  console.log(count);
};

main(require("fs").readFileSync("/dev/stdin", "UTF-8"));