#include <algorithm>
#include <cassert>
#include <cmath>
#include <iomanip>
#include <iostream>
#include <queue>
#include <tuple>
#include <vector>
using namespace std;

using F = int;
struct S {
	const int v; // neighbour
	const int r; // index of the reverse edge
	F f;         // current flow
	const F cap; // capacity
	S(int v, int ri, F c) : v(v), r(ri), f(0), cap(c) {}
};
struct FlowGraph : vector<vector<S>> {
	FlowGraph(size_t n) : vector<vector<S>>(n) {}
	void add_edge(int u, int v, F c = 1) {
		auto &t = *this;
		t[u].emplace_back(v, t[v].size(), c);
		t[v].emplace_back(u, t[u].size() - 1, 0);
	}
};

struct Dinic {
	FlowGraph &edges;
	int V, s, t;
	vector<int> l;
	vector<vector<S>::iterator> its; // levels and iterators
	Dinic(FlowGraph &edges, int s, int t)
	    : edges(edges), V(edges.size()), s(s), t(t), l(V, -1), its(V) {}
	int augment(int u, F c) { // we reuse the same iterators
		if(u == t) return c;
		for(auto &i = its[u]; i != edges[u].end(); i++) {
			auto &e = *i;
			if(e.cap > e.f && l[u] < l[e.v]) {
				auto d = augment(e.v, min(c, e.cap - e.f));
				if(d > 0) {
					e.f += d;
					edges[e.v][e.r].f -= d;
					return d;
				}
			}
		}
		return 0;
	}
	int run() {
		int flow = 0, f;
		while(true) {
			fill(l.begin(), l.end(), -1);
			l[s] = 0; // recalculate the layers
			queue<int> q;
			q.push(s);
			while(!q.empty()) {
				auto u = q.front();
				q.pop();
				for(auto &&e : edges[u])
					if(e.cap > e.f && l[e.v] < 0) l[e.v] = l[u] + 1, q.push(e.v);
			}
			if(l[t] < 0) return flow;
			for(int u = 0; u < V; ++u) its[u] = edges[u].begin();
			while((f = augment(s, 1e9)) > 0) flow += f;
		}
	}
};
struct P {
	int x, y;
};
int dist(P &l, P &r) { return (l.x - r.x) * (l.x - r.x) + (l.y - r.y) * (l.y - r.y); }
struct D {
	int b, r, dist;
	bool operator<(const D &x) { return tie(dist, b, r) < tie(x.dist, x.b, x.r); }
};

int main() {
	int n, b, r;
	cin >> n >> b >> r;
	vector<P> bs(b), rs(r);
	for(auto &p : bs) cin >> p.x >> p.y;
	for(auto &p : rs) cin >> p.x >> p.y;
	vector<D> dists;
	dists.reserve(b * r);
	for(int i = 0; i < b; ++i)
		for(int j = 0; j < r; ++j) dists.push_back({i, j, dist(bs[i], rs[j])});
	sort(dists.begin(), dists.end());
	FlowGraph g(b + r + 2);
	int s = b + r, t = b + r + 1;
	for(int i = 0; i < b; ++i) g.add_edge(s, i);
	for(int j = 0; j < r; ++j) g.add_edge(b + j, t);
	Dinic dinic(g, s, t);

	int flow    = 0;
	int maxdist = -1;
	for(auto &d : dists) {
		g.add_edge(d.b, b + d.r);
		flow += dinic.run();
		// cerr << "n=" << r + b - flow + 1 << " -> " << d.dist << '\n';
		if(flow > r + b - n) {
			maxdist = d.dist;
			goto end;
		}
	}
	assert(false);
end:;
	cout << fixed << setprecision(15) << sqrt((long double)maxdist) << endl;
	return 0;
}