#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <string>
#include <sstream>
#include <complex>
#include <algorithm>
#include <functional>
#include <vector>
#include <stack>
#include <queue>
#include <set>
#include <map>
#include <cmath>
#include <cassert>
#include <fstream>
#define REP(i,n) for(int i=0;i<n;i++)
#define FOR(a,b) for(:a<b;a++)
#define SSTR( x ) static_cast< std::ostringstream & >( \
        ( std::ostringstream() << std::dec << x ) ).str()
#define ALL(s) (s).begin(), (s).end()
using namespace std;
typedef long long unsigned int llu;
typedef long long ll;

int main (){
  int N;
  while (cin >> N){
    bool* vill = new bool[N];
    REP(i,N)vill[i] = true;
    REP(i,N){
      REP(j,N){
	string a;
	cin >> a;
	if(a == "-")continue;
	else if(a != "nyanpass")vill[j] = false;
      }
    }
    int ans = -1;
    REP(i,N){
      if(vill[i]){
	if(ans == -1){
	  ans = i + 1;
	}
	else{
	  ans = -1;
	  break;
	}
      }
    }
    
    cout << ans << endl;
  }
  return 0;
}