def qn ():
    var l1, l2, n, i
    l1 = 0
    l2 = 0
    i = 0
    while [l1 >= 0 and l2 >=0] i <= n:
        n = n - 1
        if l1 > 0:
            l1 = l1 - 1
        if l2 > 0:
            l2 = l2 - 1

        prob (1,49):
            prob(1,4):
                l1 = l1 + 3
            else:
                prob(1,1):
                    l2 = l2 + 2
                else:
                     l1 = l1 + 2
                     l2 = l2 + 1

        if l1 >= l2:
            tick l1
        else:
            tick l2