#define _USE_MATH_DEFINES
#include <algorithm>
#include <cstdio>
#include <functional>
#include <iostream>
#include <cfloat>
#include <climits>
#include <cstring>
#include <cmath>
#include <map>
#include <queue>
#include <random>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <time.h>
#include <vector>
using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> i_i;
typedef pair<ll, int> ll_i;
typedef pair<double, int> d_i;
typedef pair<ll, ll> ll_ll;
typedef pair<double, double> d_d;
struct edge { int u, v; ll w; };

ll MOD = 1000000007;
ll _MOD = 1000000009;
double EPS = 1e-10;
int INF = INT_MAX / 2;

int main() {
	int N; double PA, PB; cin >> N >> PA >> PB;
	int pa = PA * 1000, pb = PB * 1000;
	vector<int> A(N), B(N);
	for (int i = 0; i < N; i++)
		cin >> A[i];
	for (int i = 0; i < N; i++)
		cin >> B[i];
	sort(A.begin(), A.end());
	sort(B.begin(), B.end());
	random_device rd;
	mt19937 mt(rd());
	ll cnt = 0;
	for (int t = 0; t < 1000000; t++) {
		vector<int> a = A, b = B;
		int X = 0, Y = 0;
		for (int i = 0; i < N; i++) {
			int x, y;
			if (a.size() == 1 || mt() % 1000 < pa) {
				x = a[0];
				a.erase(a.begin());
			}
			else {
				int j = 1 + mt() % (a.size() - 1);
				x = a[j];
				a.erase(a.begin() + j);
			}
			if (b.size() == 1 || mt() % 1000 < pb) {
				y = b[0];
				b.erase(b.begin());
			}
			else {
				int j = 1 + mt() % (b.size() - 1);
				y = b[j];
				b.erase(b.begin() + j);
			}
			if (x > y) X += x + y;
			if (x < y) Y += x + y;
		}
		cnt += X;
	}
	printf("%.10f\n", cnt / 1000000.0);
}