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){
  long a,b,c,d;
  long count1 = 0;
  long count2 = 0;
  long count3 = 0;
  long pro1,pro2,pro3;
    int gcm,lcm;
  scanf("%ld" "%ld" "%ld" "%ld",&a,&b,&c,&d);
    
    //c,dの最大公約数
    if(c >= d){
        pro1 = c;
        pro2 = d;
    }
    if(d >= c){
        pro1 = d;
        pro2 = c;
    }
        while(pro3 != 0){
            pro3 = pro1 % pro2;
            pro1 = pro2;
            pro2 = pro3;
        }
        gcm = pro1;
    
    lcm = c * d / gcm;
   
    count1 = b / c - (a-1) / c;
    count2 = b / d - (a-1) / d;
    count3 = b / lcm - (a-1) / lcm;
    
    printf("%ld\n",b-a+1-(count1+count2-count3));

    
  return(0);
}