using System;
public class Program
{
public static void Main()
}
public static string Selam(string str)
string heyyo = "";
Random random = new Random();
List<int> di = new List <int>();
for (int i = 0; i < str.Length; i++)
int index;
do
index = random.Next(0,str.Length);
while(di.Contains(index));
heyyo+= str[index];
di.Add(index);
return heyyo;
