import sys

count = 0

for line in sys.stdin:
	array = line.readLine().split(" ")
	a = array[0]
	b = array[1]
	c = array[3]

	if (a < 1 or a > 10000) or (b < 1 or b > 10000) or (c < 1 or c > 10000):
		sys.exit()

	for x in xrange(a,b):
		if c % x == 0:
			count =  count + 1


	print count