#include <iostream>

#include <string>

#include <vector>

using namespace std;

 

int main() {

	int N;

	cin>>N;



	vector<string> greed;

 

	for(int i=0 ; i<N ; i++){

		for(int j=0 ; j<N ; j++){

			string s;

			cin>>s;

			greed.push_back(s);

		}
	}

 

	int count = 0;

	int renchon = 0;

	int check = 0;

	for(int i=0 ; i<N ; i++){

			count=0;

		for(int j=0 ; j<N ; j++){

			if(greed[N*j+i] == "nyanpass"){

				count++;

			}

		}

		if(count == N-1){

			check++;

			renchon = i+1;

		}

	}

 

	if(check==1){

		cout<<renchon<<endl;

	}else{

		cout<<-1<<endl;

	}

	return 0;
}