func_code_string: #include <bits/stdc++.h>   int main() {     double n, m;     scanf( %lf%lf , &n, &m);     int a[1000], b[1000];     for (int i = 0; i < n; i++) scanf( %d , a + i);     for (int i = 0; i < n; i++) scanf( %d , b + i);     double x;     if (b[0] != 1 && a[0] != 1) {       x = m + m / (b[0] - 1);       for (int i = n - 1; i >= 1; i--) {         if (a[i] == 1 || b[i] == 1) {           printf( -1 );           return 0;         }         x += x / (a[i] - 1);         x += x / (b[i] - 1);       }       x += x / (a[0] - 1);       printf( %.10f , x - m);     } else       printf( -1 );     return 0;   }   