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 Python (3.4.3) (judge verdict: Wrong Answer)

s=input()
a=s.replace("BC","D")[::-1]
ans=0
i=0
while i<len(a):
  if a[i]=="D":
    k=1
    while True:
      try:
        if a[i+k]=="A" or a[i+k]=="D":
          ans+=1;k+=1
        else:
          i+=k-1
          break
      except:break
  i+=1
print(ans)