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: Wrong Answer)

import math
def lcm(a,b):
    A,B=a,b
    while b!=0:
        a,b=b,a%b
    return A*B//a
 
def count(a,b,c):
    return math.floor(b/c)-math.floor((a-1)/c)
 
A,B,C,D=map(int,input().split())
C_count = count(A,B,C)
D_count = count(A,B,D)
CD_count = count(A,B,lcm(C,D))
ans = B - (A - 1) - (C_count + D_count - CD_count)
print("{}".format(ans))