#include<bits/stdc++.h>
using namespace std;
int main(){
    int n,ans=-1;
    cin>>n;
    vector<vector<string>> s(n,vector<string>(n));
    for(int i=0;i<n;++i)for(int j=0;j<n;++j)cin>>s[j][i];
    vector<int> can;
    for(int i=0;i<n;++i){
        if(count(s[i].begin(),s[i].end(),"nyanpass")==n-1)can.emplace_back(i+1);
    }
    if(can.size()==1)ans=can.front();
    cout<<ans<<endl;
}