import java.util.*;

class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();

        String[][] a = new String[n][n];
        for(int i = 0; i < n; i++) {
            for(int j = 0; j < n; j++) {
                a[i][j] = in.next();
            }
        }

        String target = "nyanpass";
        int ans = 0;
        int count = 0;

        for(int j = 0; j < n; j++) {
            boolean flag = true;
            for(int i = 0; i < n; i++) {
                if(a[i][j].equals(target))
                    continue;
                else if(a[i][j].equals("-"))
                    continue;
                else
                    flag = false;
            }
            if(flag) {
                ans = j + 1;
                count++;
            }
        }

        if(count == 1)
            System.out.println(ans);
        else
            System.out.println(-1);
    }
}