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
a, b, c, d =map(int, input().split())
lcm = (c//math.gcd(c, d))*d
cnt = (b-a+1)
c_cnt = (b//c)-((a-1)//c)
d_cnt = (b//d)-((a-1)//d)
lcm_cnt = (b//lcm)-((a-1)//lcm)
print(cnt+lcm_cnt-c_cnt-d_cnt)