Problem:
Score : 300 points

Problem Statement

There are N slimes lining up from left to right. The colors of these slimes will be given as a string S of length N consisting of lowercase English letters. The i-th slime from the left has the color that corresponds to the i-th character of S.

Adjacent slimes with the same color will fuse into one larger slime without changing the color. If there were a slime adjacent to this group of slimes before fusion, that slime is now adjacent to the new larger slime.

Ultimately, how many slimes will be there?

Constraints

1 \leq N \leq 10^5

|S| = N

S consists of lowercase English letters.

Input

Input is given from Standard Input in the following format:

N
S

Output

Print the final number of slimes.

Sample Input 1

10
aabbbbaaca

Sample Output 1

5

Ultimately, these slimes will fuse into abaca.

Sample Input 2

5
aaaaa

Sample Output 2

1

All the slimes will fuse into one.

Sample Input 3

20
xxzaffeeeeddfkkkkllq

Sample Output 3

10

Solution in Rust (1.15.1) (judge verdict: Accepted)

use std::io::BufRead;
use std::str::FromStr;

fn main() {
    let stdin = std::io::stdin();
    let mut t = Tokenizer::new(stdin.lock().lines().map(|x| x.unwrap()));

    let n: i32 = t.take();
    let s: String = t.take();
    let ans = problem( n, &s );
    println!("{}",ans);
}

fn problem( n: i32, s: &str ) -> i32 {
    let mut c:u8 = 0;
    let mut n:i32 = 0;
    for b in s.as_bytes().iter() {
        if c != *b {
            n += 1;
            c = *b;
        }
    }
    n
}

#[cfg(test)]
mod test {
    use super::*;
    #[test]
    fn test1() {
        let result = problem( 10, &"aabbbbaaca" );
        assert_eq!(result,5);
    }
    #[test]
    fn test2() {
        let result = problem( 5, &"aaaaa" );
        assert_eq!(result,1);
    }
    #[test]
    fn test3() {
        let result = problem( 20, &"xxzaffeeeeddfkkkkllq" );
        assert_eq!(result,10);
    }
}


struct Tokenizer<S: Iterator<Item = String>> {
    input: S,
    items: Vec<String>,
}

impl<S: Iterator<Item = String>> Tokenizer<S> {
    pub fn new(input: S) -> Self {
        Tokenizer {
            input: input,
            items: Vec::new(),
        }
    }

    pub fn take<T: FromStr>(&mut self) -> T {
        loop {
            if let Some(r) = self.items.pop() {
                return r.parse().ok().expect("parse failed");
            }
            let mut items = self
                .input
                .next()
                .unwrap()
                .split_whitespace()
                .map(|x| x.to_string())
                .collect::<Vec<String>>();
            items.reverse();
            self.items = items;
        }
    }
}