#include <bits/stdc++.h>

using namespace std;
using ll = long long;
// #define int ll
using PII = pair<ll, ll>;

#define FOR(i, a, n) for (ll i = (ll)a; i < (ll)n; ++i)
#define REP(i, n) FOR(i, 0, n)
#define ALL(x) x.begin(), x.end()

template<typename T> T &chmin(T &a, const T &b) { return a = min(a, b); }
template<typename T> T &chmax(T &a, const T &b) { return a = max(a, b); }
template<typename T> bool IN(T a, T b, T x) { return a<=x&&x<b; }
template<typename T> T ceil(T a, T b) { return a/b + !!(a%b); }

template<typename T> vector<T> make_v(size_t a) { return vector<T>(a); }
template<typename T,typename... Ts>
auto make_v(size_t a,Ts... ts) {
    return vector<decltype(make_v<T>(ts...))>(a,make_v<T>(ts...));
}
template<typename T,typename V> typename enable_if<is_class<T>::value==0>::type
fill_v(T &t, const V &v) { t=v; }
template<typename T,typename V> typename enable_if<is_class<T>::value!=0>::type
fill_v(T &t, const V &v ) { for(auto &e:t) fill_v(e,v); }

template<class S,class T>
ostream &operator <<(ostream& out,const pair<S,T>& a) {
    out<<'('<<a.first<<','<<a.second<<')'; return out;
}
template<class T>
ostream &operator <<(ostream& out,const vector<T>& a){
    out<<'[';
    for(const T &i: a) out<<i<<',';
    out<<']';
    return out;
}
template<class T>
ostream &operator <<(ostream& out, const set<T>& a) {
    out<<'{';
    for(const T &i: a) out<<i<<',';
    out<<'}';
    return out;
}
template<class T, class S>
ostream &operator <<(ostream& out, const map<T,S>& a) {
    out<<'{';
    for(auto &i: a) out<<i<<',';
    out<<'}';
    return out;
}

int dx[] = {0, 1, 0, -1}, dy[] = {1, 0, -1, 0}; // DRUL
const int INF = 1<<30;
const ll LLINF = 1LL<<60;
const ll MOD = 1000000007;

const double EPS = 1e-8;

using R = long double; // Rにmint渡せるようにする
using P = complex<R>;
using L = pair<P,P>;
using G = vector<P>;
struct C {
    P c; R r;
    C() {}
    C(const P &a, const R &b) : c(a), r(b) {}
};
struct S : public L {
    S() {}
    S(const P &a, const P &b) : L(a,b) {}
};

inline int sgn(const R& r) { return (r>EPS) - (r<-EPS); }
inline R dot(const P& a, const P& b) {
    return real(a)*real(b) + imag(a)*imag(b);
}
inline R det(const P& a, const P& b) {
    return real(a)*imag(b) - imag(a)*real(b);
}
inline P vec(const L& l) {return l.second - l.first;}
namespace std {
	bool operator < (const P& a, const P& b) {
		return sgn(real(a-b)) ? real(a-b) < 0 : sgn(imag(a-b)) < 0;
	}
	bool operator == (const P& a, const P& b) {
		return sgn(real(a-b)) == 0 && sgn(imag(a-b)) == 0;
	}
    bool cmp_y (const P& a, const P& b) {
        return sgn(imag(a-b)) ? imag(a-b) < 0 : sgn(real(a-b)) < 0;
    }
}

// P,L,Sについて入力
inline istream& operator>>(istream& is, P& p) {
    R x, y;
    is >> x >> y;
    p = P(x, y);
    return is;
}
inline istream& operator>>(istream& is, L& l) {
    P a, b;
    is >> a >> b;
    l = L(a, b);
    return is;
}
inline istream& operator>>(istream& is, S& s) {
    P a, b;
    is >> a >> b;
    s = S(a, b);
    return is;
}

// 線分abから見たcの位置
enum CCW{LEFT=1, RIGHT=2, BACK=4, FRONT=8, ON_SEG=16};
int ccw(P a, P b, P c) {
	P p = (c-a)/(b-a);
	if(sgn(imag(p)) > 0) return LEFT;
	if(sgn(imag(p)) < 0) return RIGHT;
	if(sgn(real(p)) < 0) return BACK;
	if(sgn(real(p)-1) > 0) return FRONT;
	return ON_SEG;
}

// 交差判定
template<bool strict=false> inline bool intersect(const L&l1, const L&l2) {
    if(strict) return sgn(det(vec(l1),vec(l2))) != 0;
    return sgn(det(vec(l1),vec(l2))) != 0 || l1 == l2;
}
// 交点 交差判定を先にすること!!!
inline P crosspoint(const L& l1, const L& l2) {
    R ratio = det(vec(l2), l2.first-l1.first)/det(vec(l2),vec(l1));
    return l1.first + vec(l1)*ratio;
}

// 凸多角形polを直線lで切断して左側の多角形を返す
G convex_cut(const G& pol, const L& l) {
    G res;
    REP(i, pol.size()) {
        P a = pol[i], b = pol[(i + 1)%pol.size()];
        int da = sgn(det(l.first-a, l.second-a)), db = sgn(det(l.first-b, l.second-b));
        if (da >= 0) res.emplace_back(a);
        if (da * db < 0) res.emplace_back(crosspoint(L{a, b}, l));
    }
    return res;
}

signed main(void)
{
    cin.tie(0);
    ios::sync_with_stdio(false);

    while(1) {
        ll n;
        cin >> n;
        if(!n) break;
        G pol(n);
        REP(i, n) cin >> pol[i];

        G ret(4);
        ret[0] = {-100, -100}, ret[1] = {10100, -100}, ret[2] = {10100, 10100}, ret[3] = {-100, 10100};
        REP(i, n-1) {
            L l({pol[i], pol[i+1]});
            ret = convex_cut(ret, l);
            // cout << ret << endl;
        }
        L l({pol[n-1], pol[0]});
        ret = convex_cut(ret, l);
        // cout << ret << endl;
        if(ret.size() >= 3) cout << 1 << endl;
        else cout << 0 << endl;
    }

    return 0;
}



Measured memory_bytes: 3280