using System.Collections.Generic;
public static void Main()
Console.Write("Ingresa una frase: ");
frase = Console.ReadLine();
List<int> nuevo = new List<int>();
int tmp = r.Next(0, frase.Length);
if(nuevo.IndexOf(tmp) < 0)
if(nuevo.Count == frase.Length)
for(int x = 0; x < frase.Length; x++)
frase2 += frase[nuevo[x]];
Console.WriteLine(frase2);