//No.239 にゃんぱすー
#pragma GCC optimize("O3")
#pragma GCC target("avx")
#include <bits/stdc++.h>
#define rep(i ,n) for(int i=0;i<(int)(n);++i)
#define repr(i ,n) for(int i=n;i>(int)(n);--i)
#define rep1(i ,n) for(int i=1;i<=(int)(n);++i)
#define ALL(a) a.begin(), a.end()
#define RSORT(a) sort(ALL(a),greater<>())
#define SORT(a) sort(ALL(a))
#define bit_check(bit, i) ((bit>>(i)) & 1)
#define PRINT(x) cout << (x) << endl;
#define ENDL cout << endl;
using namespace std;
typedef long long int i64;
typedef unsigned long long u64;
template<class T> using V = vector<T>;
using VI = V<int>;
const int INF = 2e9;
const i64 MOD = 1e9 + 7;

template <class T> inline bool chmin(T& a, T b){if(a>b){a=b; return true;} return false;}
template <class T> inline bool chmax(T& a, T b){if(a<b){a=b; return true;} return false;}
struct Init_On{
    Init_On(){
        cin.tie(nullptr);
        ios_base::sync_with_stdio(false);
        cout << fixed << setprecision(16);
    }
};

signed main(){
    int n; cin >> n;
    string a[n][n];
    rep( i , n ){
        rep( j , n ){
            cin >> a[i][j];
        }
    }
    int ren = 0;
    int nyan_num;
    rep( i , n ){
        int nyan = 0;
        rep( j , n ){
            if(a[i][i] == "-" && a[j][i] == "nyanpass"  ) { ++nyan; ++ren; }
        }
        if( nyan != n - 1) { ren -= nyan; }
        else { ren = n - 1; nyan_num = i + 1;}
    }
    if( ren == n - 1 ) cout << nyan_num << endl;
    else cout << -1 << endl;
}