#include <bits/stdc++.h>

using namespace std;

inline int toInt(string s) {int v; istringstream sin(s);sin>>v;return v;}
template<class T> inline string toString(T x) {ostringstream sout;sout<<x;return sout.str();}
template<class T> inline T sqr(T x) {return x*x;}

typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<string> vs;
typedef pair<int, int> pii;
typedef long long ll;

#define all(a)  (a).begin(),(a).end()
#define rall(a) (a).rbegin(), (a).rend()
#define pb push_back
#define mp make_pair
#define each(i,c) for(typeof((c).begin()) i=(c).begin(); i!=(c).end(); ++i)
#define exist(s,e) ((s).find(e)!=(s).end())
#define range(i,a,b) for(int i=(a);i<(b);++i)
#define rep(i,n)  range(i,0,n)
#define clr(a,b) memset((a), (b) ,sizeof(a))
#define dump(x)  cerr << #x << " = " << (x) << endl;
#define debug(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ")" << " " << __FILE__ << endl;

const double eps = 1e-3;
const double pi  = acos(-1.0);
const ll INF =1LL << 62;
const int inf =1 << 29;

long double Lagrange_interpolation(vector<long double> xi,vector<long double> fi,long double x){
	int n=xi.size()-1;
	long double f=0.0;
	for(int i=0;i<=n;++i){
		long double li=1.0;
		for(int j=0;j<=n;++j){
			if(i==j) continue;
			li*=(x-xi[j])/(xi[i]-xi[j]);
		}
		f+=fi[i]*li;
	}
	return f;
}

int main(void){
	int d;
	while(cin >> d){
		if(d==0) break;

		bool ok[8]={false};
		vector<long double> di(d+3);
		for(int i=0;i<=d+2;++i) cin >> di[i];

		for(int i=0;i<=d+2;++i){
			for(int j=i+1;j<=d+2;++j){
				vector<long double> xi;
				vector<long double> fi;
				for(int k=0;k<=d+2;++k){
					if(k==i||k==j) continue;
					xi.pb(k);
					fi.pb(di[k]);
				}
				long double vi=Lagrange_interpolation(xi,fi,i);
				long double vj=Lagrange_interpolation(xi,fi,j);
				if(abs(vi-di[i])<eps) ok[i]|=true;
				if(abs(vj-di[j])<eps) ok[j]|=true;
			}
		}
		for(int i=0;i<=d+2;++i) if(!ok[i]) cout << i << endl;
	}
	return 0;
}