Problem:
Score : 300 points

Problem Statement

You are given four integers A, B, C, and D. Find the number of integers between A and B (inclusive) that can be evenly divided by neither C nor D.

Constraints

1\leq A\leq B\leq 10^{18}

1\leq C,D\leq 10^9

All values in input are integers.

Input

Input is given from Standard Input in the following format:

A B C D

Output

Print the number of integers between A and B (inclusive) that can be evenly divided by neither C nor D.

Sample Input 1

4 9 2 3

Sample Output 1

2

5 and 7 satisfy the condition.

Sample Input 2

10 40 6 8

Sample Output 2

23

Sample Input 3

314159265358979323 846264338327950288 419716939 937510582

Sample Output 3

532105071133627368

Solution in PyPy3 (2.4.0) (judge verdict: Accepted)

def main():
	a,b,c,d = map(int,input().split())

	#about c
	ans_c_a = (a-1)//c
	ans_c_b = b//c
	# print(ans_c_b)
	ans_c = ans_c_b - ans_c_a
	# print("ans_c = {}".format(ans_c))

	#about d
	ans_d_a = (a-1)//d
	ans_d_b = b//d
	ans_d = ans_d_b - ans_d_a
	# print("ans_d = {}".format(ans_d))

	#aboud c*d
	import fractions
	saisyou = (c * d) // fractions.gcd(c,d)
	# print(saisyou)
	ans_saisyou_a = (a-1)//saisyou
	ans_saisyou_b = b//saisyou
	ans_saisyou = ans_saisyou_b - ans_saisyou_a
	# print("ans_saisyou = {}".format(ans_saisyou))

	print(int( b-a+1 - (ans_c + ans_d - ans_saisyou) ))


if __name__ == '__main__':
	main()