public class ABCSequence {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String s = sc.next();
		String sub = "abc";
		int n = s.length();
		int k = sub.length();
		long[][] f = new long[n + 1][k + 1];
		f[0][0] = 1;
		for (int i = 1; i <= n; i++) {
			f[i][0] = 1;
			for (int j = 1; j <= k; j++) {
				char c1 = s.charAt(i - 1);
				char c2 = sub.charAt(j - 1);
				if (c1 == c2) {
					f[i][j] = f[i - 1][j - 1] + f[i - 1][j];
				} else {
					f[i][j] = f[i - 1][j];
				}
			}
		}
		System.out.println(f[n][k]);
		sc.close();
	}

}