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 Python (3.4.3) (judge verdict: Runtime Error)

import math

S = input().split()
A = int(S[0])
B = int(S[1])
C = int(S[2])
D = int(S[3])

E = (C * D) / math.gcd(C, D)
X = math.floor(B/C) - math.floor(A/C)
Y = math.floor(B/D) - math.floor(A/D)
Z = math.floor(B/E) - math.floor(A/E)

print(int(B-A-X-Y+Z))