use proconio::{input, marker::Chars};
fn main() {
    input! {
        n: usize,
        a: Chars,
    }
    let mut cnt = vec![];
    for i in 1..n {
        if a[i] == 'o' && a[i-1] == 'x' {
            cnt.push(i+1);
        }
    }
    println!("{}", cnt.len());
    for c in &cnt {
        print!("{} ", c);
    }
    println!();
}