/*Bismillahir Rahmanir Raheem*/
#include <bits/stdc++.h>
  
using namespace std;

#define kuka ios::sync_with_stdio(false);cin.tie(0), cout.tie(0);
#define pb push_back
#define sz(x) x.size()
#define all(x) x.begin(), x.end()
#define FOR(n) for(int i = 0; i < n; i++)
#define ff(x, y) for( int y = 0; y < x; y++)
#define fff(x, y) for( int y = x; y <= 0; y--)
#define F first
#define S second
//#define int long long  

typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

const ll INF = LLONG_MAX;
const int inf = INT_MAX;
const int N = 1e5 + 5;
const int MOD = 1e9 + 7;	 

int n, L;
ld d[N], v[N];
ld pref_t[N], pref_s[N];

ld get() {
    ld ans = 1e15;

    for (int i = 1; i <= n; i++) {
        pref_t[i] = pref_t[i - 1] + ((ld)d[i] / (ld)v[i]);
        pref_s[i] = pref_s[i - 1] + d[i];
    }

    for (int i = 1; i <= n; i++) {
        int l = i - 1, r = n + 1;

        while (r - l > 1) {
            int mid = (l + r) / 2;
            if (pref_s[mid] - pref_s[l] < L) {
                l = mid;
            } else {
                r = mid;
            }
        }

        ld sum = pref_t[i - 1] + pref_t[n] - pref_t[l];
        if (l < n) {
            ld last = L - (pref_s[l] - pref_s[i - 1]);
            if (l + 1 <= n) {
                sum += last / v[l + 1];
            }
        }
        ans = min(ans, sum);
    }

    return ans;
}

void oyan() {
    cin >> n >> L;
    for (int i = 1; i <= n; i++) {
        cin >> d[i];
    }
    for (int i = 1; i <= n; i++) {
        cin >> v[i];
    }

    ld ans1 = get();

    reverse(d + 1, d + n + 1);
    reverse(v + 1, v + n + 1);

    ld ans2 = get();

    cout << fixed << setprecision(9) << min(ans1, ans2) << "\n";
}


main(){
    kuka;
	//freopen("test.txt", "r", stdin);
	//freopen("distance.in", "r", stdin);
    //freopen("distance.out", "w", stdout);
    int oylan = 1;
    //cin>>oylan;
    while(oylan--){
        oyan();
    }
}
/*
NOTES
a/b module == (a*b^(module - 2)) % (module);

ll binpow(int n, int k) {
	if (k == 0) {
		return 1;
	}if (k % 2 == 0) {
		ll val = binpow(n, (k / 2));
		return val * val % MOD;
	}
	return (binpow(n, k - 1) * n) % MOD;
}
*/