#include<iostream>
#include<string>
#include<string.h>
#include<algorithm>
#include<stdio.h>
#include<cmath>
#include<vector>
#include<utility>
#include<stack>
#include<queue>
#include<list>
#include<bitset>

#define FOR(i, a, b) for(int i=(a);i<=(b);i++)
#define RFOR(i, a, b) for(int i=(a);i>=(b);i--)
#define MOD 1000000007
#define INF 1000000000

using namespace std;


int main(void) {
	int n;
	char a[101][101][31];
	int count = 0;
	int point = -1;

	cin >> n;
	FOR(i, 1, n) {
		FOR(t, 1, n) {
			cin >> a[i][t];
		}
	}
	FOR(i, 1, n) {
		FOR(t, 1, n) {
			if (i == t) {
				if (t==n) {
					point = i;
					count++;
				}
				continue;
			}
			if (strcmp("nyanpass", a[t][i]) != 0) {
				break;
			}
			if (t == n) {
				point = i;
				count++;
			}
		}
	}
	if (count == 1) {
		cout << point << endl;
	}
	else {
		cout << -1 << endl;
	}
	return 0;
}