Count 'xx' Substrings

Background

Congcong is currently learning about string processing. He encountered an interesting problem that requires counting the occurrences of a specific substring within a given string.

Problem Description

Count the number of "xx" in the given string. Overlapping is allowed, so "xxx" contains 2 "xx".

Input Format

Input is given from standard input in the following format.

A string $S$.

Output Format

Output is printed to standard output in the following format.

An integer, representing the count of "xx".

Sample

abcxx

1

xxx

2

xxxx

3

Sample Explanation

For the input "xxx\