Can anyone help me convert This C++ code to C#?

#include <iostream>

using namespace std;

const int positive = 5;

int main ()
{
     int n;
     cout << "Enter the number of students, and grades are separated by spaces:";
     cin >> n;
     int * p = new int [n];
     for (int i = 0; i < n; i++) p [i] = 0;
     int sum = 0, Hmany = 0 failed = 0;
     for (int i = 0; i < n; i++)
     {
         if (p [i] < positive)
         {
             if (!failed) cout << "students did not write:";
             failed ++;
             cout << '' << i;
         }
         sum + = p [i];
         Hmany ++;
     }
    cout << endl << n-failed << " studens passed, " << failed << " failed, groups average - " << (double)sum/Hmany << endl;
    return 0;
}