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 gcd(long long a,long long b){
  if(b == 0){
    return a;
  }
  gcd(b,a%b);
}
  

int main(void){
  long long a , b , c , d;
  scanf("%lld %lld %lld %lld",&a,&b,&c,&d);
  if(d < c){
    long long temp = d;
    d = c;
    c = temp;
  }
  long long k = gcd(c,d);
  long long g = k;
  g *= c/k;
  g *= d/k;
  
  long long len = b-a;
  
  //printf("%lld %lld\n",k,g);
  printf("%lld\n",len - (len/c) - (len/d) + (len/g));
  
  return 0;
}