using System;

​

public class Program

{

    public static void Main()

    {

        //for w3resource

        string str = "w3resource";

        int pos = 0;

        char replacement = 'e';

        str = str.Remove(pos, 1).Insert(pos, replacement.ToString());

        string str2 = str;

        int pos2 = 9;

        char replacement2 = 'w';

        str = str.Remove(pos2, 1).Insert(pos2, replacement2.ToString());

        Console.WriteLine(str);

        // for Python

        string str3 = "Python";

        int pos3 = 0;

        char replacement3 = 'n';

        str3 = str3.Remove(pos3, 1).Insert(pos3, replacement3.ToString());

        string str4 = str3;

        int pos4 = 5;

        char replacement4 = 'P';

        str4 = str3.Remove(pos4, 1).Insert(pos4, replacement4.ToString());

        Console.WriteLine(str4);

    }

}