func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     ios::sync_with_stdio(false);     int n, w;     cin >> n >> w;     vector<int> a(n), b(n);     for (int& v : a) cin >> v;     for (int& v : b) cin >> v;     double l = 0, r = 2e9;     for (int t = 0; t < 500; t++) {       double m = (l + r) / 2;       double now = m;       for (int i = 0; i < n && now >= 0; i++) {         now -= (w + now) / a[i];         if (now < 0) break;         now -= (w + now) / b[(i + 1) % n];       }       if (now >= 0)         r = m;       else         l = m;     }     if (r == 2e9)       cout << -1 <<   n ;     else       cout << fixed << setprecision(10) << r <<   n ;   }   