#include<iostream> #include<vector> #include<string> #include<algorithm> #include<map> #include<set> #include<utility> #include<cmath> #include<cstring> #include<queue> #include<stack> #include<cstdio> #include<sstream> #include<iomanip> #include<assert.h> #define loop(i,a,b) for(int i=a;i<b;i++) #define rep(i,a) loop(i,0,a) #define pb push_back #define all(in) in.begin(),in.end() #define shosu(x) fixed<<setprecision(x) using namespace std; //kaewasuretyuui typedef long long ll; typedef pair<int,int> pii; typedef vector<int> vi; typedef vector<vi> vvi; typedef vector<pii> vp; typedef vector<vp> vvp; typedef vector<string> vs; typedef vector<double> vd; typedef vector<vd> vvd; typedef pair<int,pii> pip; typedef vector<pip>vip; const double PI=acos(-1); const double EPS=1e-7; const int inf=1e8; const ll INF=1e16; int dx[4]={0,1,0,-1}; int dy[4]={1,0,-1,0}; int main(){ int n; cin>>n; vector<vs>in(n,vs(n)); rep(i,n)rep(j,n)cin>>in[i][j]; vi out; rep(i,n){ bool h=true; rep(j,n)if(i!=j&&in[j][i]!="nyanpass")h=false; if(h)out.pb(i); } if(out.size()==1)cout<<out[0]+1<<endl; else cout<<-1<<endl; }