#include <iostream>
#include <sstream>
#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <ctime>
#include <cstring>
#include <string>
#include <vector>
#include <stack>
#include <queue>
#include <deque>
#include <map>
#include <set>
#include <bitset>
#include <numeric>
#include <utility>
#include <iomanip>
#include <algorithm>
#include <functional>
#include <unordered_map>
using namespace std;

#define REP(i, s) for (int i = 0; i < s; ++i)
#define ALL(v) (v.begin(), v.end())
#define COUT(x) cout << #x << " = " << (x) << " (L" << __LINE__ << ")" << endl
#define EACH(i, s) for (__typeof__((s).begin()) i = (s).begin(); i != (s).end(); ++i)

template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
template<class T1, class T2> ostream& operator << (ostream &s, pair<T1,T2> P)
{ return s << '<' << P.first << ", " << P.second << '>'; }
template<class T> ostream& operator << (ostream &s, vector<T> P)
{ for (int i = 0; i < P.size(); ++i) { if (i > 0) { s << " "; } s << P[i]; } return s; }
template<class T> ostream& operator << (ostream &s, vector<vector<T> > P)
{ for (int i = 0; i < P.size(); ++i) { s << endl << P[i]; } return s << endl; }
template<class T> ostream& operator << (ostream &s, set<T> P)
{ EACH(it, P) { s << "<" << *it << "> "; } return s << endl; }
template<class T1, class T2> ostream& operator << (ostream &s, map<T1,T2> P)
{ EACH(it, P) { s << "<" << it->first << "->" << it->second << "> "; } return s << endl; }



////////////////////////////
// 基本要素 (点, 線分, 円)
////////////////////////////

using DD = double;
const DD INF = 1LL<<60;      // to be set appropriately
const DD EPS = 1e-10;        // to be set appropriately
const DD PI = acos(-1.0);
DD torad(int deg) {return (DD)(deg) * PI / 180;}
DD todeg(DD ang) {return ang * 180 / PI;}

/* Point */
struct Point {
    DD x, y;
    Point(DD x = 0.0, DD y = 0.0) : x(x), y(y) {}
    friend ostream& operator << (ostream &s, const Point &p) {return s << '(' << p.x << ", " << p.y << ')';}
};
inline Point operator + (const Point &p, const Point &q) {return Point(p.x + q.x, p.y + q.y);}
inline Point operator - (const Point &p, const Point &q) {return Point(p.x - q.x, p.y - q.y);}
inline Point operator * (const Point &p, DD a) {return Point(p.x * a, p.y * a);}
inline Point operator * (DD a, const Point &p) {return Point(a * p.x, a * p.y);}
inline Point operator * (const Point &p, const Point &q) {return Point(p.x * q.x - p.y * q.y, p.x * q.y + p.y * q.x);}
inline Point operator / (const Point &p, DD a) {return Point(p.x / a, p.y / a);}
inline Point conj(const Point &p) {return Point(p.x, -p.y);}
inline Point rot(const Point &p, DD ang) {return Point(cos(ang) * p.x - sin(ang) * p.y, sin(ang) * p.x + cos(ang) * p.y);}
inline Point rot90(const Point &p) {return Point(-p.y, p.x);}
inline DD cross(const Point &p, const Point &q) {return p.x * q.y - p.y * q.x;}
inline DD dot(const Point &p, const Point &q) {return p.x * q.x + p.y * q.y;}
inline DD norm(const Point &p) {return dot(p, p);}
inline DD abs(const Point &p) {return sqrt(dot(p, p));}
inline DD amp(const Point &p) {DD res = atan2(p.y, p.x); if (res < 0) res += PI*2; return res;}
inline bool eq(const Point &p, const Point &q) {return abs(p - q) < EPS;}
inline bool operator < (const Point &p, const Point &q) {return (abs(p.x - q.x) > EPS ? p.x < q.x : p.y < q.y);}
inline bool operator > (const Point &p, const Point &q) {return (abs(p.x - q.x) > EPS ? p.x > q.x : p.y > q.y);}
inline Point operator / (const Point &p, const Point &q) {return p * conj(q) / norm(q);}

/* Line */
struct Line : vector<Point> {
    Line(Point a = Point(0.0, 0.0), Point b = Point(0.0, 0.0)) {
        this->push_back(a);
        this->push_back(b);
    }
    friend ostream& operator << (ostream &s, const Line &l) {return s << '{' << l[0] << ", " << l[1] << '}';}
};

/* Circle */
struct Circle : Point {
    DD r;
    Circle(Point p = Point(0.0, 0.0), DD r = 0.0) : Point(p), r(r) {}
    friend ostream& operator << (ostream &s, const Circle &c) {return s << '(' << c.x << ", " << c.y << ", " << c.r << ')';}
};


int ccw(const Point &a, const Point &b, const Point &c) {
    if (cross(b-a, c-a) > EPS) return 1;
    if (cross(b-a, c-a) < -EPS) return -1;
    if (dot(b-a, c-a) < 0) return 2;
    if (norm(b-a) < norm(c-a)) return -2;
    return 0;
}

Point proj(Point p, Line l) {
    DD t = dot(p - l[0], l[1] - l[0]) / norm(l[1] - l[0]);
    return l[0] + (l[1] - l[0]) * t;
}
Point refl(Point p, Line l) {
    return p + (proj(p, l) - p) * 2;
}
bool isinterPL(Point p, Line l) {
    return (abs(p - proj(p, l)) < EPS);
}
bool isinterPS(Point p, Line s) {
    return (ccw(s[0], s[1], p) == 0);
}
bool isinterLL(Line l, Line m) {
    return (abs(cross(l[1] - l[0], m[1] - m[0])) > EPS ||
            abs(cross(l[1] - l[0], m[0] - l[0])) < EPS);
}
bool isinterSS(Line s, Line t) {
    if (eq(s[0], s[1])) return isinterPS(s[0], t);
    if (eq(t[0], t[1])) return isinterPS(t[0], s);
    return (ccw(s[0], s[1], t[0]) * ccw(s[0], s[1], t[1]) <= 0 && 
            ccw(t[0], t[1], s[0]) * ccw(t[0], t[1], s[1]) <= 0);
}
DD distancePL(Point p, Line l) {
    return abs(p - proj(p, l));
}
DD distancePS(Point p, Line s) {
    Point h = proj(p, s);
    if (isinterPS(h, s)) return abs(p - h);
    return min(abs(p - s[0]), abs(p - s[1]));
}
DD distanceLL(Line l, Line m) {
    if (isinterLL(l, m)) return 0;
    else return distancePL(m[0], l);
}
DD distanceSS(Line s, Line t) {
    if (isinterSS(s, t)) return 0;
    else return min(min(distancePS(s[0], t), distancePS(s[1], t)), min(distancePS(t[0], s), distancePS(t[1], s)));
}



vector<Point> crosspoint(Line l, Line m) {
    vector<Point> res;
    DD d = cross(m[1] - m[0], l[1] - l[0]);
    if (abs(d) < EPS) return vector<Point>();
    res.push_back(l[0] + (l[1] - l[0]) * cross(m[1] - m[0], m[1] - l[0]) / d);
    return res;
}
vector<Point> crosspoint(Circle e, Circle f) {
    vector<Point> res;
    DD d = abs(e - f);
    if (d < EPS) return vector<Point>();
    if (d > e.r + f.r + EPS) return vector<Point>();
    if (d < abs(e.r - f.r) - EPS) return vector<Point>();
    DD rcos = (d * d + e.r * e.r - f.r * f.r) / (2.0 * d), rsin;
    if (e.r - abs(rcos) < EPS) rsin = 0;
    else rsin = sqrt(e.r * e.r - rcos * rcos);
    Point dir = (f - e) / d;
    Point p1 = e + dir * Point(rcos, rsin);
    Point p2 = e + dir * Point(rcos, -rsin);
    res.push_back(p1);
    if (!eq(p1, p2)) res.push_back(p2);
    return res;
}
vector<Point> crosspoint(Circle e, Line l) {
    vector<Point> res;
    Point p = proj(e, l);
    DD rcos = abs(e - p), rsin;
    if (rcos > e.r + EPS) return vector<Point>();
    else if (e.r - rcos < EPS) rsin = 0;
    else rsin = sqrt(e.r * e.r - rcos * rcos);
    Point dir = (l[1] - l[0]) / abs(l[1] - l[0]);
    Point p1 = p + dir * rsin;
    Point p2 = p - dir * rsin;
    res.push_back(p1);
    if (!eq(p1, p2)) res.push_back(p2);
    return res;
}

vector<Point> crosspoint_LS(Line l, Line s) {
    vector<Point> res;
    DD d = cross(s[1] - s[0], l[1] - l[0]);
    if (abs(d) < EPS) return vector<Point>();
    Point p = l[0] + (l[1] - l[0]) * cross(s[1] - s[0], s[1] - l[0]) / d;
    if (isinterPS(p, s)) res.push_back(p);
    return res;
}
vector<Point> crossPoint_LPo(Line l, vector<Point> ps) {
    int n = ps.size();
    vector<Point> res;
    for (int i = 0; i < n; ++i) {
        int f = i, t = (i+1)%n;
        Line s(ps[f], ps[t]);
        vector<Point> temp = crosspoint_LS(l, s);
        for (int j = 0; j < temp.size(); ++j) {
            bool exist = false;
            for (int k = 0; k < res.size(); ++k) {
                if (eq(res[k], temp[j])) exist = true;
            }
            if (!exist) res.push_back(temp[j]);
        }
    }
    return res;
}


// convex cut
int ccw_for_convexcut(const Point &a, const Point &b, const Point &c) {
    if (cross(b-a, c-a) > EPS) return 1;
    if (cross(b-a, c-a) < -EPS) return -1;
    if (dot(b-a, c-a) < 0) return 2;
    if (norm(b-a) < norm(c-a)) return -2;
    return 0;
}
vector<Point> crosspoint_for_convexcut(const Line &l, const Line &m) {
    vector<Point> res;
    DD d = cross(m[1] - m[0], l[1] - l[0]);
    if (abs(d) < EPS) return vector<Point>();
    res.push_back(l[0] + (l[1] - l[0]) * cross(m[1] - m[0], m[1] - l[0]) / d);
    return res;
}
vector<Point> ConvexCut(const vector<Point> &pol, const Line &l) {
    vector<Point> res;
    for (int i = 0; i < pol.size(); ++i) {
        Point p = pol[i], q = pol[(i+1)%pol.size()];
        if (ccw_for_convexcut(l[0], l[1], p) != -1) {
            if (res.size() == 0) res.push_back(p);
            else if (!eq(p, res[res.size()-1])) res.push_back(p);
        }
        if (ccw_for_convexcut(l[0], l[1], p) * ccw_for_convexcut(l[0], l[1], q) < 0) {
            vector<Point> temp = crosspoint_for_convexcut(Line(p, q), l);
            if (temp.size() == 0) continue;
            else if (res.size() == 0) res.push_back(temp[0]);
            else if (!eq(temp[0], res[res.size()-1])) res.push_back(temp[0]);
        }
    }
    return res;
}

// Voronoi-diagram (今回は使わない)
Line bisector(const Point &p, const Point &q) {
    Point c = (p + q) / 2.0L;
    Point v = (q - p) * Point(0.0L, 1.0L);
    v = v / abs(v);
    return Line(c - v, c + v);
}
vector<Point> Voronoi(vector<Point> pol, const vector<Point> &ps, int ind) {
    for (int i = 0; i < ps.size(); ++i) {
        if (i == ind) continue;
        Line l = bisector(ps[ind], ps[i]);
        pol = ConvexCut(pol, l);
    }
    return pol;
}





int main() {
    int N, M;
    cin >> N;
    vector<Point> pol(N);
    for (int i = 0; i < N; ++i) cin >> pol[i].x >> pol[i].y;
    cin >> M;
    vector<Point> ps(M);
    for (int i = 0; i < M; ++i) cin >> ps[i].x >> ps[i].y;
    double res = 0.0;
    for (int i = 0; i < M; ++i) {
        vector<Point> npol = Voronoi(pol, ps, i);
        for (auto p : npol) {
            double tmp = 1LL<<60;
            for (int j = 0; j < M; ++j) tmp = min(tmp, abs(ps[j] - p));
            res = max(res, tmp);
        }
    }
    cout << fixed << setprecision(10) << res << endl;
}



Measured memory_bytes: 3304