import java.util.*;

class Main {
        public static void main(String args[]) {
                try (Scanner sc = new Scanner(System.in)) {
                        int N = sc.nextInt();
                        boolean[] f = new boolean[N];
                        for (int i = 0; i < N; i++) {
                                f[i] = true;
                        }
                        for (int i = 0; i < N; i++) {
                                for (int j = 0; j < N; j++) {
                                        String S = sc.next();
                                        if (!(S.equals("-") || S.equals("nyanpass"))) {
                                                f[j] = false;
                                        }
                                }
                        }
                        int c = 0;
                        for (int i = 0; i < N; i++) {
                                if (f[i]) {
                                        c++;
                                }
                        }
                        if (c != 1) {
                                System.out.println(-1);
                        } else {
                                for (int i = 0; i < N; i++) {
                                        if (f[i]) {
                                                System.out.println(i + 1);
                                        }
                                }
                        }
                }
        }
}