#include <iostream>
#include <vector>
#include <string>
#include <algorithm>

using namespace std;

int main() {

    std::ios::sync_with_stdio(false);
    std::cin.tie(0);

    int n;
    cin >> n;
    vector<vector<int>> vec(n, vector<int>(n));
    for (int i = 0; i < n; ++i) {
        for (int j = 0; j < n; ++j) {
            string s;
            cin >> s;
            if (s == "nyanpass") {
                vec[i][j] = 1;
            } else if(s == "-") {
                vec[i][j] = 2;
            } else {
                vec[i][j] = 0;
            }
        }
    }
    vector<int> renchon(n, 1);
    for (int j = 0; j < n; ++j) {
        for (int i = 0; i < n; ++i) {
            if (vec[i][j] == 0) {
                renchon.at(j) = 0;
                break;
            }
        }
    }
    if (count(renchon.begin(), renchon.end(), 1) == 1) {
        auto ans = find(renchon.begin(), renchon.end(), 1) - renchon.begin();
        cout << ans + 1 << endl;
    } else {
        cout << "-1" << endl;
    }
    return 0;
}