Count Pairs in String

Background

Congcong is studying the properties of strings. He has defined a special way of "pairing".

Problem Description

We'll say that a "pair" in a string is two instances of a character separated by exactly one character. So "AxA" the 'A's make a pair. Pairs can overlap, so "AxAxA" contains 3 pairs -- 2 for 'A' and 1 for 'x'. Recursively compute the number of pairs in the given string.

Input Format

Input is given from standard input in the following format.

s

Output Format

Output to standard output in the following format.

count

Sample

axa

1

axax

2

axbx

1

Sample Explanation

For Sample 1 "axa\