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>

long long int lcm(long long int a, long long int b){
	long long int x, tmp, r;
 x = a * b;
 
  if(a<b){
    tmp = a;
    a = b;
    b = tmp;
  }
 
  r = a % b;
  while(r!=0){
    a = b;
    b = r;
    r = a % b;
  }

	return x/b;
}

int main(){
	long long int a, b, c, d;
	scanf("%lld %lld %lld %lld", &a, &b, &c, &d);
	long long int i, ans=0, x, y, z;
    
    x = (b-a+1+a%c)/c;
    y = (b-a+1+a%d)/d;
    z = (b-a+1+a%lcm(c,d))/lcm(c,d);
    if (a%c==0) x++;
    
    printf("%d %d %d ", x, y, z);
	
	printf("%lld", (b-a+1)-x-y+z);
	
	return 0;
}