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(){
  long A,B,C,D;
  long ans=0;
  scanf("%ld %ld %ld %ld",&A,&B,&C,&D);
  ans=B-A-1;
  ans-=(B/C-A/C-1)+(B/D-A/D-1);
  for(long te=C*D;te<=B;te+=C*D)
   ans++;
  //if(A%C==0)ans--;
  //if(A%D==0)ans--;
  printf("%ld\n",ans);

  return 0;
}