public static void Main()
var input = "input".ToCharArray();
char[] charList = new char[input.Length];
for (int i = 0; i < 3; i++)
for (int j = 1; j < input.Length; j++)
charList[j - 1] = input[j];
charList[charList.Length - 1] = temp;
charList = new char[input.Length];
Console.WriteLine(string.Join("", input));