#include<iostream>
#include<iomanip>
#include<algorithm>
#include<vector>
#include<string>
#include<math.h>

#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define REP(i,n) for(int i=0;i<(n);i++)
#define ALL(i) (i).begin(),(i).end()
#define rALL(i) (i).rbegin(),(i).rend()
#define debug(x) cout<<#x<<": "<<x<<endl
#define pi M_PI

typedef long long ll;
typedef unsigned long long ull;

using namespace std;

int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);
/*-------- code --------*/
    int n;
    int poi;
    int flag = 0;
    string a[100][100];

    cin >> n;
    REP(i,n){
        REP(j,n){
            cin >> a[i][j];
        }
    }

    REP(j,n){
        int cnt = 0;
        REP(i,n){
            if(a[i][j] == "nyanpass") cnt++;
        }
        if(cnt == n - 1){
            poi = j+1;
            flag++;
        }
    }

    if(flag == 1) cout << poi << endl;
    else cout << -1 << endl;
}