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 Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)

import java.util.Scanner;

public class Main {
  public static void main(String[] args) {
    Scanner in = new Scanner(System.in);
    long st = in.nextLong();
    long en = in.nextLong();
    long mod1 = in.nextLong();
    long mod2 = in.nextLong();
    in.close();
    long mod1and2 = lcmul(mod1, mod2);
    long countand = en / mod1and2;
    countand -= (st - 1) / mod1and2;
        long countor = en / mod1 - (st - 1) / mod1 + en / mod2 - (st - 1) / mod2;
    long ans = en - st - countor + countand  + 1;
    System.out.println(ans);
  }
  public static long gcdiv(long a, long b) {
    while (a != b) {
      if (a > b) {
        a -= b * (a / b);
        if (a == 0) {
          a = b;
        }
      } else if (b > a) {
        b -= a * (b / a);
        if (b == 0) {
          b = a;
        }
      }
    }
    return a;
  }
  public static long lcmul(long a, long b) {
    long gcdiv = gcdiv(a, b);
    a /= gcdiv;
    b /= gcdiv;
    return a * b * gcdiv;
  }
  public static long lcmul(long a, long b, long gcdiv) {
    a /= gcdiv;
    b /= gcdiv;
    return a * b * gcdiv;
  }
}