#include <cstdio>
#include <cstring>
#include <cmath>
#include <iostream>
#include <list>
#include <stack>
#include <queue>
#include <vector>
#include <map>
#include <string>
#include <utility>
#include <algorithm>
#include <numeric>
#include <functional>

#define FOR(i,a,b) for (int i=(a);i<(b);i++)
#define RFOR(i,a,b) for (int i=(b)-1;i>=(a);i--)
#define REP(i,n) for (int i=0;i<(n);i++)
#define RREP(i,n) for (int i=(n)-1;i>=0;i--)
#define ALL(a) (a).begin(),(a).end()

using namespace std;
typedef long long ll;

int N;
string A[110][110];
vector<int> renchonppoi;


int main(int argc, char *argv[])
{
  cin.tie(0);
  ios::sync_with_stdio(false);

  cin >> N;
  REP(i,N) REP(j,N) cin >> A[i][j];
  REP(j,N) {
    bool nyampass = true;
    REP(i,N) {
      if ("-" == A[i][j] || "nyanpass" == A[i][j])
        continue;
      nyampass = false;
      break;
    }
    if (nyampass)
      renchonppoi.push_back(j);
  }
  if (renchonppoi.size() != 1) {
    cout << -1 << endl;
    return 0;
  }
  cout << renchonppoi[0] + 1 << endl;

  return 0;
}