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 Pascal (FPC 2.6.2) (judge verdict: Accepted)

var s,p:ansistring;
    i,j,t:longint;
    a:int64;
begin
  readln(s);
  i:=1;
  while i<=length(s) do
  begin
    if s[i]='A' then
      inc(t);
    if s[i]='B' then
      if (i<>length(s))and(s[i+1]='C') then
      begin
        inc(a,t);
        inc(i,2);
        continue;
      end
      else
        t:=0;
    if s[i]='C' then
      t:=0;
    inc(i);
  end;
  writeln(a);
end.