use proconio::input;
use proconio::marker::Chars;

fn main () {
    input! {
        _: usize,
        s: Chars,
    }
    let s = s.iter().collect::<String>();
    let s = s.replace("CPCTCPC", "CPCTF");
    //println!("{}", s);
    let ans = s.matches("CPCTF").count();
    println!("{}", ans);
}