С# hanin

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text.RegularExpressions;

class Program
{
static void Main(string[] args)
{
string[] lastYear = { "Анна", "Иван", "Петр", "Мария" };
string[] thisYear = { "Иван", "Мария" };

    string[] fallen = FindFallen(lastYear, lastYear.Length, thisYear, thisYear.Length);

    Console.WriteLine("Ребята, которые скатились:");
    foreach (var name in fallen)
    {
        if (name != null) // Проверка, чтобы не печатать null значения
        {
            Console.WriteLine(name);
        }
    }
}

static string[] FindFallen(string[] A, int Na, string[] B, int Nb)
{
    string[] fallen = new string[Na];
    int k = 0;

    for (int i = 0; i < Na; i++)
    {
        bool found = false;
        for (int j = 0; j < Nb; j++)
        {
            if (A[i] == B[j])
            {
                found = true;
                break;
            }
        }

        if (!found)
        {
            fallen[k] = A[i];
            k++;
        }
    }

    return fallen;
}

}