static int counter = 0;
    public int maxstrairs = 100;
    
    void Start()
    {
        counter++;
        if(counter < maxstrairs)
        {
            dothestairs();
        }

    }

    private void dothestairs()
    {
        if (counter % 2 == 0)
        {
            // even
        }
        else
        {
           // odd
        }
    }