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 C (GCC 5.4.1) (judge verdict: Wrong Answer)

#include<stdio.h>

int main(void){
    int a, b, c, d;
    int x1, x2, y1, y2, z1, z2, r, s, ans;

    scanf("%d %d %d %d", &a, &b, &c, &d);

    x1 = c / a;
    x2 = d / a;

    y1 = c / b;
    y2 = d / b;

    s = a * b;
    r = b % a;
    while(r!=0){
        b = a;
        a = r;
        r = b % a;
    }

    s = s / a;

    z1 = c / s;
    z2 = d / s;

    ans = b - a - (x2 - x1) - (y2 - y1) + (z2 - z1);

    printf("%d", ans);
}