i don't really understand why it's asking to do it with 2 stacks

class Solution {
    private static List<int> oneStack = new List<int>();

    static void Main(String[] args) {
        var q = int.Parse(Console.In.ReadLine()!.TrimEnd()); // number of queries
        for(var i=0; i<q; i++){
            var a = Console.In.ReadLine()!.TrimEnd().Split(" ").Select(x => int.Parse(x)).ToArray();
            var t = a[0];
            switch(t){
                case 1:
                    enqueue(a[1]);
                    break;
                case 2:
                    dequeue();
                    break;
                case 3: 
                    print();
                    break;
                default:
                    throw new Exception($"t={t}");
            }
        }
    }

    static void enqueue(int x){
        oneStack.Add(x);
    }

    static void dequeue(){
        oneStack = oneStack.Skip(1).ToList();
    }

    static void print(){
        Console.WriteLine(oneStack.First());
    }
}