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)

from collections import defaultdict, deque
import sys
import heapq
import bisect
import math
import itertools
import string
import queue
import copy
import time
from fractions import gcd
sys.setrecursionlimit(10**8)
INF = float('inf')
mod = 10**9+7
eps = 10**-7

def inp(): return int(sys.stdin.readline())
 
def inp_list(): return list(map(int, sys.stdin.readline().split()))

def lcm(x, y): return (x * y) // gcd(x, y)

A, B, C, D = inp_list()
total = B - A + 1
ans = total - (total + 1) // C - (total + 1) // D + (total + 1) // lcm(C, D)
print(ans)