The string of letters is given. How many times the subsequence "\textbf{ABA}" occurs in the given string? The letters "\textbf{ABA}" may not be adjacent, but their order must be preserved. \InputFile One line containing only uppercase Latin letters. The length of the string does not exceed $10^6$. \OutputFile Print the number of occurrences of the subsequence "\textbf{ABA}" in the string.