use std::io::prelude::*;
use std::io;
use std::fs::File;
use std::str::FromStr;
use std::io::BufReader;
#[cfg(local)]
fn buf_read() -> io::Result<(Vec<String>)> {
    let f = try!(File::open("input.txt"));
    let input_lines: Vec<_> = BufReader::new(f).lines().collect();
    let lines: Vec<String> = input_lines.into_iter().map(|e| e.unwrap()).collect();
    Ok((lines))
}

#[cfg(not(local))]
fn buf_read() -> io::Result<(Vec<String>)> {
    let stdin = io::stdin();
    let input_lines: Vec<_> = stdin.lock().lines().collect();
    let lines: Vec<String> = input_lines.into_iter().map(|e| e.unwrap()).collect();
    Ok((lines))
}

fn main() {
    type Element = String;
    let input = buf_read().unwrap();
    let mut input_vectors: Vec<Vec<Element>> = vec![];
    for input_line in input {
        let input_str: Vec<String> = input_line.split(' ').map(String::from).collect();
        let mut input_vector: Vec<Element> = vec![];
        for input_elem_str in input_str {
            let elem: Element = Element::from_str(input_elem_str.as_str()).unwrap();
            input_vector.push(elem);
        }
        input_vectors.push(input_vector);
    }
    let stones = input_vectors[0][0].chars();
    let mut previous_stone = input_vectors[0][0].chars().next().unwrap();
    let mut sum = 0;
    for stone in stones {
        if previous_stone != stone {
            sum += 1
        };
        previous_stone = stone;
    }
    println!("{}", sum);
}