use proconio::input;
fn main() {
    input! {
        n:usize,
        list: [[String;n];n],
    }
    let mut count = 0;
    for i in 0..n{
        let mut diff = false;
        if count > 1{break};
        for j in 0..n{
            if list[j][i] != "nyanpass" && list[j][i] != "-"{
                diff = true;
                break;
            }
        }
        if !diff{
            count += 1;
        }
    }

    if count != 1{
        println!("-1");
    }else{
        for i in 0..n{
            if list[0][i] == "nyanpass"{
                println!("{}",i + 1);
            }
        }
    }
}