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 Ruby (2.3.3) (judge verdict: Wrong Answer)

s=gets.chomp
k = 0
n=0
i = 0
while i = s.index('ABC', i)
  i+= 2
  n+=1
end
k+=n

n=0
i = 0
while i = s.index('AABC', i)
  i+= 1
  n+=1
end
k+=n


n=0
i = 0
while i = s.index('ABCBC', i)
  i+= 1
  n+=1
end
k+=n



n=0
i = 0
while i = s.index('ABCABC', i)
  i+= 1
  n+=1
end
k+=n


n=0
i = 0
while i = s.index('BCAABC', i)
  i+= 1
  n+=1
end
k+=n
puts k