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 Fortran (gfortran v4.8.4) (judge verdict: Time Limit Exceeded)

program kenken
 implicit none
 integer n, k, i, j, sum
 character(200000) s
 sum=0
 n=1
 j=1
 k=len_trim(s)
 read*, s
a: do while(n.ne.0)
 do i=j,k
  n=index(s,"ABC")
   if(n.ne.0) then
   s(n:n+2)="BCA"
   sum=sum+1
   j=n
   cycle a
   end if
 end do
 end do a
   if(n.eq.0) then
   print*, sum
   return
   end if
end program