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 C (GCC 5.4.1) (judge verdict: Time Limit Exceeded)

#include <stdio.h>

int main(void) {
    char a[200001];
    int count = 0;
    
    scanf("%s",a);
    
    for(int i = 0;i < 200001;i++){
        if(a[i] == 'A' && a[i + 1] == 'B'&& a[i+2] == 'C'){
            a[i] = 'B';
            a[i+1] = 'C';
            a[i+2] = 'A';
            count++;
            i = 0;
        }
        if(a[i] == '\0'){
            break;
        }
        
    }
    printf("%d",count);
	return 0;
}