#include <bits/stdc++.h>
using namespace std;
typedef pair<int,int> PII;
typedef long long LL;
typedef unsigned long long ULL;
template<class T> inline bool amax (T &a, const T &b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool amin (T &a, const T &b) { if (a > b) { a = b; return 1; } return 0; }
template<class T> ostream& operator << (ostream &os, const vector<T> &v) { os << "["; for (typename vector<T>::const_iterator it = v.begin(); it != v.end(); it++) { os << (it != v.begin() ? ", " : "") << *it; } os << "]"; return os; }
template<class T> ostream& operator << (ostream &os, const set<T> &s) { os << "{"; for (typename set<T>::const_iterator it = s.begin(); it != s.end(); it++) { os << (it != s.begin() ? ", " : "") << *it; } os << "}"; return os; }
template<class K, class V> ostream& operator << (ostream &os, const map<K, V> &m) { os << "{"; for (typename map<K, V>::const_iterator it = m.begin(); it != m.end(); it++) { os << (it != m.begin() ? ", " : "") << it->first << "->" << it->second; } os << "}"; return os; }
template<class T, class S> ostream& operator << (ostream &os, const pair<T, S> &p) { os << "(" << p.first << ", " << p.second << ")"; return os; }
template <class T> istream& operator >> (istream &is, vector<T> &v) { for (size_t i = 0; i < v.size(); i++) is >> v[i]; return is; }
template <class T, class S> inline T lexical_cast (const S &s) { T t; stringstream ss; ss << s; ss >> t; return t; }

//> v < ^ (clock wise)
int dx[] = {1,0,-1,0};
int dy[] = {0,1,0,-1};
const int INFI = 1<<28;
const long long int INFL = 1LL<<60;
const float INFF = 1e+100;
const double INFD = 1e+300;
const double EPS = 1e-8;
const long long int MOD = 1000000007;

void solve ();
int main () {
    cout.setf(ios::fixed); cout.precision(10);
    ios_base::sync_with_stdio(false);
    solve();
    return 0;
}

void solve () {
    int N;
    cin >> N;
    vector<bool> a(N, true);
    for (int i = 0; i < N; i++) {
        for (int j = 0; j < N; j++) {
            string s; cin >> s;
            if (s == "-") continue;
            a[j] = a[j] & (s == "nyanpass");
        }
    }
    int ans = -1;
    for (int i = 0; i < N; i++) {
        if (a[i]) ans = i+1;
    }
    cout << ans << endl;
}