func_code_string: #include <bits/stdc++.h>   using namespace std;   double ans = 1;   int p, d, h;   int main() {     cin >> p >> d >> h;     int top = 0;     int kh;     for (int i = 1; i <= d; i++) {       int x;       cin >> x;       top += x;       if (i == h) {         kh = x;       }     }     if (top < p) {       cout << -1;       return 0;     } else {       double t = 1;       int temp = top - 1;       for (int i = p - 1; i > 0; i--) {         t *= ((double)temp / (double)i);         temp--;       }       double ist = 1;       int temp2 = top - kh;       for (int i = p - 1; i > 0; i--) {         ist *= ((double)temp2 / (double)i);         temp2--;       }       double aist = t - ist;       ans = aist / t;       cout << ans;     }     return 0;   }   