#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <climits>
#include <cmath>
#include <complex>
#include <map>
#include <set>
#include <vector>
#include <stack>
#include <queue>
#include <bitset>
#include <algorithm>
#include <numeric>
#include <functional>
#include <cassert>
#include <iomanip>
#include <random>
using namespace std;

#define Rep(b, e, i) for(int i = b; i <= e; i++)
#define Repr(e, b, i) for(int i = e; i >= b; i--)
#define rep(n, i) Rep(0, n-1, i)
#define repr(n, i) Repr(n-1, 0, i)
#define all(v) (v).begin(), (v).end()
#define pb(v) push_back(v)
#define mp make_pair
#define uniq(v) (v).erase(unique(all(v)),(v).end())
#define bitcnt(x) __builtin_popcount(x)
#define fst first
#define snd second
#define Pqaz(T) priority_queue<T,vector<T>,greater<T>>
#define Pqza(T) priority_queue<T>
#define put(x) cout << x;
#define putsp(x) cout << x << ' ';
#define putln(x) cout << x << endl;
#define ENJYU std::ios::sync_with_stdio(false);std::cin.tie(0);

typedef long long ll;
typedef pair<ll, ll> llP;
typedef pair<int, int> intP;
typedef complex<double> comp;
typedef vector <int> vec;
typedef vector <ll> vecll;
typedef vector <double> vecd;
typedef vector <vec> mat;
typedef vector <vecll> matll;
typedef vector <vecd> matd;

//vector の中身を出力
template <class T>ostream &operator<<(ostream &o,const vector<T>&v)
{o<<"{";for(int i=0;i<(int)v.size();i++)o<<(i>0?", ":"")<<v[i];o<<"}";return o;}

const int MAX = 200020;
const double PI = 3.14159265358979323846;
const double EPS = 1e-12;
const int INF = 1<<29;
const ll INFL = 1e18;
const int MOD = 1000000007;

int dx4[4]={1,0,-1,0};
int dy4[4]={0,1,0,-1};
int dx8[8]={1,0,-1,1,-1,1,0,-1};
int dy8[8]={1,1,1,0,0,-1,-1,-1};

//********************************template END****************************************//

void solve(void){

	int N, Q = 1000000;
	double p1, p2;
	cin >> N >> p1 >> p2;

	vec as(N), bs(N);

	rep(N, i)
	{
		cin >> as[i];
	}
	rep(N, i)
	{
		cin >> bs[i];
	}

	sort(all(as));
	sort(all(bs));

	int pa = p1*1000, pb = p2*1000;

	vec wa(1000, 1), wb(1000, 1);
	rep(1000-pa, i)
	{
		wa[i] = 0;
	}
	rep(1000-pb, i)
	{
		wb[i] = 0;
	}

	random_device rnd;
	mt19937 mt(rnd());
	uniform_int_distribution<> randN(0, 999);

	int win = 0;

	rep(Q, q)
	{

		int sa = 0, sb = 0;
		vec va = as, vb = bs;

		repr(N-1, n)
		{
			int na = 0, nb = 0;

			uniform_int_distribution<> randp(0, n);

			if (wa[randN(mt)])
			{
				na = va[0];
				va.erase(va.begin());
			}
			else
			{
				int i = randp(mt) + 1;
				na = va[i];
				va.erase(va.begin()+i);
			}

			if (wb[randN(mt)])
			{
				nb = vb[0];
				vb.erase(vb.begin());
			}
			else
			{
				int j = randp(mt) + 1;
				nb = vb[j];
				vb.erase(vb.begin()+j);
			}

			if (na > nb)
			{
				sa += na + nb;
			}
			else
			{
				sb += na + nb;
			}

		}

		if (va[0] > vb[0])
		{
			sa += va[0] + vb[0];
		}
		else
		{
			sb += va[0] + vb[0];
		}

		if (sa > sb)
		{
			win++;
		}

	}

	cout << fixed << setprecision(4) << (double)win/Q << endl;

}

int main(void){
	solve();
	//cout << "yui(*-v・)yui" << endl;
	return 0;
}