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>
#include<string.h>
#include<stdlib.h>
#include<math.h>

int main(){

  long long a,b;
  long long c,d;
  long long r,l;
  long long e,f,g;
  long long n,m,k;

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

  r = b - a;
  e = r/c;
  f = r/d;

  n = d; m = c;
  do{
    k = n % m;
    n = m; m = k;
  }while(k != 0);

  l = (c*d)/n;
  g = r/l;

  printf("%lld", r - e - f + g);

  return 0;
}