#include <iostream>
#include <vector>
#include <set>

using namespace std;

int main() {
	
	int n; cin >> n;
	vector<vector<string>> a(n,vector<string>(n,""));
	vector<int> arr(n,0);
	for(int i = 0; i < n; i++){
	    for(int j = 0; j < n; j++){
	        cin >> a[i][j];
	        if(a[i][j] == "nyanpass") arr[j] += 1;
	    }
	}
	
	int test = 0;
	for(int it:arr)if(it == 2)test++;
	if(test != 1){ cout << -1; return 0; }
	for(int i = 0; i < n; i++) {
	    if(arr[i] == 2){
	        cout << i + 1;
	        return 0;
	    }
	}
	
	return 0;
}