fn main() {
    let mut n = String::new();
    std::io::stdin().read_line(&mut n).ok();
    let n: usize = n.trim().parse().unwrap();

    let mut xx = String::new();
    std::io::Read::read_to_string(&mut std::io::stdin(), &mut xx).ok();
    let xx: Vec<String> = xx.split_whitespace().flat_map(str::parse).collect();

    let mut answer = None;

    for i in 0..n {
        if (0..n)
            .map(|j| &xx[j * n + i])
            .all(|g| g == "-" || g == "nyanpass")
        {
            if answer.is_some() {
                println!("-1");
                return;
            }

            answer = Some(i);
        }
    }

    answer.map_or_else(|| println!("-1"), |i| println!("{}", i + 1));
}