# deterministic version takes 0.5.max(0, n-1).max(0, n-2)
# probabilistic version takes (1/p_1)*(1/p_2).0.5.max(0, n-1).max(0, n-2)

def f():
    var m, n, r

    while n > 0:
        r = unif(0,1)
        n = n - r
        m = n

        while m > 0:
            prob(1,2):
            	m = m - 1
            tick 1