using System;
class Program
{
static String removeChars(String s, String chars) {
int i = 0, internal_i = 0;
char[] arr = s.ToCharArray();
while (i != arr.Length) {
char ch = arr[i];
if (chars.ToLower().IndexOf(ch) == -1) {
arr[internal_i] = arr[i];
internal_i ++;
}
i++;
}
s = new String(arr);
return s.Substring(0, internal_i);
}
static void Main()
{
String first = "c# programming language";
String second = "rogb";
String s = removeChars(second, first);
Console.WriteLine(s);
}
}
/*
run:
b
*/
