func_code_string: #include <bits/stdc++.h>   using namespace std;   int main() {     ios::sync_with_stdio(false);     cin.tie(NULL);     int n, m;     cin >> n >> m;     double lift[n], land[n];     for (int i = 0; i < (n); i++) cin >> lift[i] >> land[i];     double ans = 0;     for (int i = n - 1; i >= 0; i--) {       ans = (ans + m / land[(i + 1) % n]) / (1 - 1 / land[(i + 1) % n]);       if (ans < 0 || ans > 1e9) return !(cout << -1);       ans = (ans + m / lift[i]) / (1 - 1 / lift[i]);       if (ans < 0 || ans > 1e9) return !(cout << -1);     }     cout << fixed << setprecision(7) << ans;   }   