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)

# n = int(sys.stdin.readline())
# a, b = map(int, sys.stdin.readline().split())
# c = list(map(int, sys.stdin.readline().split()))
# s = [list(map(int,list(sys.stdin.readline()))) for i in range(h)]  # 二次元配列入力　二次元マップみたいな入力のとき

# a = 100
# b = 0.987654321
# print('{0:06d}-{1:6f}'.format(a,b))  # 0埋め, 小数点出力桁指定時のときの出力
# 000100-0.987654

import math
import sys
import itertools
import queue
from functools import reduce
from fractions import gcd

def lcm(a, b):
    return a * b / gcd(a, b)

mod = 1000000007

if __name__ == "__main__":
    A, B, C, D = map(int, sys.stdin.readline().split())
    A = A - 1
    c_div = int(B // C)
    d_div = int(B // D)
    cd_div = int(B // lcm(C, D))

    not_div1 = B - (c_div + d_div -cd_div)

    c_div = int(A // C)
    d_div = int(A // D)
    cd_div = int(A // lcm(C, D))

    not_div2 = A - (c_div + d_div -cd_div)

    print(not_div1 - not_div2)