static void main()
{
    int guests, busLim, busCount, tableLim, tableCount, boatLim, boatCount;

    Console.WriteLine("How many people did you invite?");
    guests = int.Parse(Console.ReadLine());
    Console.WriteLine("How many seats are available in a bus?");
    busLim = int.Parse(Console.ReadLine());
    Console.WriteLine("How many seats are available in a table?");
    tableLim = int.Parse(Console.ReadLine());
    Console.WriteLine("How many seats are available in a boat?");
    boatLim = int.Parse(Console.ReadLine());

    busCount = CalcAmount(guests, busLim);
    tableCount = CalcAmount(guests, tableLim);
    boatCount = CalcAmount(guests, boatLim);

    Console.WriteLine("For {0} guests you need {1} buses, {2} tables and {3} boats", guests, busCount, tableCount, boatCount);
}

public static int CalcAmount(int guests, int limit)
{
    int vehicles = guests/limit; // מספרת הרכבים יהיה מספר המוזמנים חלקי כמות האנשים שנכנסת לרכב אחד
    if(guests % limit != 0)      // אם ישנה שארית - נוסיף עוד רכב
        vehicles++;

    return vehicles;
}