#include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>
#include <iomanip>
#include <stack>
#include <algorithm>
#include <string>
#include <map>
#include <iterator>
#include <set>
#include <queue>
#include <bitset>
#include <cassert>

using namespace std;


int main() {

    int N;
    cin >> N;
    vector<int> vs(N, 0);

    for (int i = 0; i < N; ++i) {
        for (int j = 0; j < N; ++j) {
            string A;
            cin >> A;
            if (A == "nyanpass") {
                vs[j] += 1;
            }
        }
    }

    int num = -1;
    bool found = false;
    for (int i = 0; i < N; ++i) {
        if (vs[i] == N - 1) {

            if (found) {
                num = -1;
                break;
            } else {
                num = i + 1;
                found = true;
            }
        }
    }

    cout << num << endl;

    return 0;
}