#include <bits/stdc++.h>

using namespace std;

ifstream fin("secv3.in");
ofstream fout("secv3.out");

const int NMax = 30005;

long long t[NMax], s[NMax], sp[NMax];

long long cmmdc(long long x, long long y){
    long long m;
    while(y > 0){
        m = x % y;
        x = y;
        y = m;
    }
    return x;
}

long long cmmmc(long long x, long long y){
    return (x * y) / cmmdc(x, y);
}

long long amplificare(int N){
    long long ans = t[1];
    for(int i = 2; i <= N; ++ i){
        ans = cmmmc(ans, t[i]);
    }
    for(int i = 1; i <= N; ++ i){
        s[i] *= (ans / t[i]);
    }
    return ans;
}

double query(int N, long long amplif, int lng){
    double ans = -1;
    for(int i = lng; i <= N; ++ i){
        ans = max(ans, (sp[i] - sp[i - lng]) * 1.0 / lng);
    }
    return ans * 1.0 / amplif;
}

int main()
{
    int N, L, U;
    fin >> N >> L >> U;
    for(int i = 1; i <= N; ++ i){
        fin >> s[i];
    }
    for(int i = 1; i <= N; ++ i){
        fin >> t[i];
    }
    long long amplif = amplificare(N);
    sp[1] = s[1];
    for(int i = 2; i <= N; ++ i){
        sp[i] = sp[i - 1] + s[i];
    }
    double ans = query(N, amplif, L);
    fout << setprecision(4) << ans << '\n';
    return 0;
}