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: Runtime Error)

import java.util.*;
class Main {
  public static int gcd(int m, int n) {
    if (m % n == 0) {
      return n;
    } else {
	  int remainder = m % n;
      return gcd(n, remainder);
    }
  }
  
  public static int findNum(int a, int b, int c, int d) {
    int lcm = c * d / gcd(c, d);
    
    int numOfC = b/c - ((a-1)/c);
    int numOfD = b/d - ((a-1)/d);
    int numOfLcm = b/lcm - ((a-1)/lcm);
    
    return (b-a+1) - (numOfC + numOfD - numOfLcm);
  }
  
  public static void main(String args[]) {
    Scanner sc = new Scanner(System.in);
    int a = Integer.parseInt(sc.next());
    int b = Integer.parseInt(sc.next());
    int c = Integer.parseInt(sc.next());
    int d = Integer.parseInt(sc.next());
    
    int result = findNum(a, b, c, d);
    System.out.println(result);
  }
}