#include <iostream>
#include <vector>
#include <string>
#include <cstring>
#include <math.h>
#include <cmath>
#include <limits.h>
#include <map>
#include <set>
#include <queue>
#include <algorithm>
#include <functional>
#include <stdio.h>
using namespace std;

long long MOD = 1000000007;

int main() {
    
    int N;
    cin >> N;
    
    vector< vector<string> > V(N);
    
    for ( int i = 0; i < N; i++ ) {
    for ( int j = 0; j < N; j++ ) {
        string s;
        cin >> s;
        V[i].push_back(s);
    }
    }
    
    vector<int> renchons;
    for ( int i = 0; i < N; i++ ) {
        bool renchon = true;
        for ( int j = 0; j < N; j++ ) {
            if ( V[j][i] != "nyanpass" && V[j][i] != "-" ) { renchon = false; }
        }
        if ( renchon ) { renchons.push_back(i+1); }
    }
    
    if ( renchons.size() >= 2 || !renchons.size() ) { cout << -1 << endl; }
    else { cout << renchons[0] << endl; }
    
    return 0;
}