use proconio::input;

fn main() {
    input! {
        n:usize,
        list: [[String;n];n],
    }
    let mut count = 0;
    let mut index = 0;
    for i in 0..n{
        if count > 1{break};
        for j in 0..n{
            if list[j][i] != "nyanpasu" && list[j][i] != "-"{
                continue;
            }
            index = j;
            count += 1;
        }
    }
    if count != 1{
        println!("-1");
    }else{
        println!("{}",index + 1);
    }
}