#include <iostream>
#include <algorithm>
#include <string>
#include <vector>
#include <map>
#include <set>
#include <stdio.h>
#include <cstring>
#include <queue>
#include <stack>
#include <functional>
#include <math.h>
#include <iomanip>
using namespace std;
#define Would
#define you
const int INF = 999999999;
const int MOD = 1e9 + 7;
const double pi = 3.141592653589793238;

int n, ans, cou;
bool rentyon[105];
int main() {
	cin >> n;
	string h;
	for (int i = 0; i < n; ++i) {
		for (int j = 0; j < n; ++j) {
			cin >> h;
			if (h == "nyanpass") { rentyon[j + 1] = 1; }
		}
	}
	for (int i = 0; i <= n; ++i) {
		if (rentyon[i]) {
			++cou;
			ans = i;
		}
	}
	if (cou == 1) { cout << ans << endl; }
	else { cout << -1 << endl; }
}