#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <sstream>
#include <cstdio>
#include <cstdlib>

using namespace std;

string a[101][101];

int main(){
    
    //string str;
    int N;
    cin >> N;
    for (int i = 0; i < N; i += 1)
    {
        for (int j = 0; j < N; j += 1)
        {
            cin >> a[i][j];
        }
    }
    int count = 0;
    int idx = -1;
    for (int j = 0; j < N; j += 1)
    {
        bool is = true;
        for (int i = 0; i < N; i += 1)
        {
            if(not(a[i][j] == "nyanpass" or a[i][j] == "-"))
                is = false;
        }
        if(is){
            count++;
            idx = j;
        }
    }
    if(count == 1)
        cout << idx+1 << endl;
    else
        cout << -1 << endl;
    

    return 0;
}