#[allow(unused)]
use proconio::{input, marker::Chars};

fn main() {
    input! {
        n: usize,
        s: Chars,
    }
    let mut cnt = 0;
    let mut a = Vec::new();
    for i in 1..n {
        if s[i] == 'o' && s[i - 1] == 'x' {
            a.push(i + 1);
            cnt += 1;
        }
    }
    println!("{}", cnt);
    if cnt > 0 {
        print!("{}", a[0]);
        for x in a[1..].iter() {
            print!(" {}", x)
        }
    }
    println!()
}