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())
cd=int(c*d/(math.gcd(c,d)))
#print(cd)
c1=b//c
c2=(a-1)//c
c3=c1-c2
d1=b//d
d2=(a-1)//d
d3=d1-d2
cd1=b//(cd)
cd2=(a-1)//(cd)
cd3=cd1-cd2
print((b-a+1)-(c3+d3-cd3))
#print(str(c3)+" "+str(d3)+" "+str(cd3))