def max2nd(a):
    if len(a) <= 1:
	return None
    mx = a[0]
    lastmax = a[0]
    van = False
    for i in range(len(a)):
	if a[i] > mx:
	    lastmax = mx
	    mx = a[i]
	    van = True
    if (not van):
	return None
    return lastmax