#[allow(unused_imports)]
use std::cmp;

// Input macro from https://qiita.com/tanakh/items/0ba42c7ca36cd29d0ac8
macro_rules! input {
  (source = $s:expr, $($r:tt)*) => {
    let mut iter = $s.split_whitespace();
    input_inner!{iter, $($r)*}
  };
  ($($r:tt)*) => {
    #[allow(unused_mut)]
    let mut s = {
      use std::io::Read;
      let mut s = String::new();
      std::io::stdin().read_to_string(&mut s).unwrap();
      s
    };
    let mut iter = s.split_whitespace();
    input_inner!{iter, $($r)*}
  };
}

macro_rules! input_inner {
  ($iter:expr) => {};
  ($iter:expr, ) => {};

  ($iter:expr, $var:ident : $t:tt $($r:tt)*) => {
    let $var = read_value!($iter, $t);
    input_inner!{$iter $($r)*}
  };
}

macro_rules! read_value {
  ($iter:expr, ( $($t:tt),* )) => {
    ( $(read_value!($iter, $t)),* )
  };

  ($iter:expr, [ $t:tt ; $len:expr ]) => {
    (0..$len).map(|_| read_value!($iter, $t)).collect::<Vec<_>>()
  };

  ($iter:expr, chars) => {
    read_value!($iter, String).chars().collect::<Vec<char>>()
  };

  ($iter:expr, usize1) => {
    read_value!($iter, usize) - 1
  };

  ($iter:expr, $t:ty) => {
    $iter.next().unwrap().parse::<$t>().expect("Parse error")
  };
}

// 1-indexed
// example: Bit::new(n, |x, y| *x += *y, 0)
struct Bit<T, F> {
    n: usize,
    dat: Vec<T>,
    op: F,
    unit: T,
}

impl<T: Clone, F: Fn(&mut T, &T)> Bit<T, F> {
    #[allow(dead_code)]
    fn new(n: usize, op: F, unit: T) -> Self {
        Bit {
            n: n,
            dat: vec![unit.clone(); n + 1],
            op: op,
            unit: unit,
        }
    }
    #[allow(dead_code)]
    fn from_vec(mut v: Vec<T>, op: F, unit: T) -> Self {
        let n = v.len();
        let mut dat = vec![unit.clone()];
        dat.append(&mut v);
        for i in 1..n {
            let j = i as i32;
            let b = (j & -j) as usize;
            let x = dat[i].clone();
            op(&mut dat[i + b], &x);
        }
        Bit {
            n: n,
            dat: dat,
            op: op,
            unit: unit,
        }
    }
    fn operate(&mut self, k: usize, a: &T) {
        let mut k = k;
        while k <= self.n {
            (self.op)(&mut self.dat[k], &a);
            let l = k as i32;
            k += (l & -l) as usize;
        }
    }
    fn accum(&self, k: usize) -> T {
        let mut k = k;
        let mut sum = self.unit.clone();
        while k > 0 {
            (self.op)(&mut sum, &self.dat[k]);
            let l = k as i32;
            k -= (l & -l) as usize;
        }
        sum
    }
}

fn sub(token: Vec<bool>) -> i64 {
  let mut bit = Bit::new(token.len(), |x, y| *x += *y, 0i64);
  for (i, &a) in token.iter().enumerate() {
    if a {
      bit.operate(i + 1, &1);
    }
  }
  let mut sum = 0;
  for (i, &a) in token.iter().enumerate() {
    if ! a {
      sum += bit.accum(i + 1);
    }
  }
  sum
}

fn main() {
  input! {
    s: chars,
  }
  let s = s;
  let mut ans = 0;
  let mut token = vec![];
  let mut prev_b = false;
  for &c in s.iter() {
    if c == 'A' {
      if prev_b {
        ans += sub(token);
        token = vec![true];
        prev_b = false;
      } else {
        token.push(true);
      }
    } else if c == 'C' {
      if prev_b {
        token.push(false);
        prev_b = false;
      } else {
        ans += sub(token);
        token = vec![];
        prev_b = false;
      }
    } else {
      if prev_b {
        ans += sub(token);
        token = vec![];
      } else {
        prev_b = true;
      }
    }
  }
  if ! token.is_empty() {
    ans += sub(token);
  }

  println!("{}", ans);
}


Measured memory_bytes: 8444