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: Accepted)

#include<stdio.h>
int Euclid(long int c, long int d){
  long int tmp;
  if(c<d){
    tmp=c;
    c=d;
    d=tmp;
  }
  long int r=c%d;
  while(r!=0){
  c=d;
  d=r;
  r=c%d;
  }
  return d;
}
int main(){
  long int a, b, c, d;
  scanf("%ld %ld %ld %ld", &a, &b, &c, &d);
  long int r, div;
  r=Euclid(c,d);
  div=c*d/r;
  long int n=b-b/c-b/d+b/div-(a-1-(a-1)/c-(a-1)/d+(a-1)/div);
  printf("%ld", n);
  return 0;
}