#ifdef LOCAL111
#else
	#define NDEBUG
#endif
#include <bits/stdc++.h>
const int INF = 1e8;
using namespace std;

#define endl '\n'
#define ALL(a)  (a).begin(),(a).end()
#define SZ(a) int((a).size())
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define RFOR(i,a,b) for (int i=(b)-1;i>=(a);i--)
#define REP(i,n)  FOR(i,0,n)
#define RREP(i,n) for (int i=(n)-1;i>=0;i--)
#define RBP(i,a) for(auto& i : a)
#ifdef LOCAL111
	#define DEBUG(x) cout<<#x<<": "<<(x)<<endl
	template<typename T> void dpite(T a, T b){ for(T ite = a; ite != b; ite++) cout << (ite == a ? "" : " ") << *ite; cout << endl;}
#else
	#define DEBUG(x) true
	template<typename T> void dpite(T a, T b){ return; }
#endif
#define F first
#define S second
#define SNP string::npos
#define WRC(hoge) cout << "Case #" << (hoge)+1 << ": "
#define rangej(a,b,c) ((a) <= (c) and (c) < (b))
#define rrangej(b,c) rangej(0,b,c)
template<typename T> void pite(T a, T b){ for(T ite = a; ite != b; ite++) cout << (ite == a ? "" : " ") << *ite; cout << endl;}
template<typename T> bool chmax(T& a, T b){if(a < b){a = b; return true;} return false;}
template<typename T> bool chmin(T& a, T b){if(a > b){a = b; return true;} return false;}

typedef long long int LL;
typedef unsigned long long ULL;
typedef pair<int,int> P;
typedef pair<LL,LL> LP;

void ios_init(){
	cout.setf(ios::fixed);
	cout.precision(12);
#ifdef LOCAL111
	return;
#endif
	ios::sync_with_stdio(false); cin.tie(0);	
}

int main()
{
	ios_init();
	int n;
	double pa, pb;
	while(cin >> n >> pa >> pb){
		vector<int> a(n);
		vector<int> b(n);
		REP(i, n) cin >> a[i];
		REP(i, n) cin >> b[i];
		sort(ALL(a)); sort(ALL(b));
		random_device rnd;
		mt19937 mt(rnd());
		uniform_real_distribution<double> rd(0.,1.);
		int cnta = 0, cntb = 0;
		for(int cnt = 0; cnt < 100000; ++cnt) {
			vector<int> va(ALL(a));
			vector<int> vb(ALL(b));
			int sca = 0;
			int scb = 0;
			for(int i = 0; i < n; ++i) {
				int ac;
				int bc;
				if(i == n-1 or rd(mt) <= pa){
					ac = va[0];
					va.erase(va.begin());	
				}else{
					int p = rnd()%(SZ(va)-1)+1;
					ac = va[p];
					va.erase(va.begin()+p);
				}
				if(i == n-1 or rd(mt) <= pb){
					bc = vb[0];
					vb.erase(vb.begin());
				}else{
					int p = rnd()%(SZ(vb)-1)+1;
					bc = vb[p];
					vb.erase(vb.begin()+p);
				}
				if(ac > bc){
					sca += ac+bc;
				}else{
					scb += ac+bc;
				}
			}
			// DEBUG(sca); DEBUG(scb);
			if(sca > scb) cnta++;
			else if(sca < scb) cntb++;
		}
		DEBUG(cnta); DEBUG(cntb);
		cout << double(cnta)/(cnta+cntb) << endl;
	}
	return 0;
}