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 <math.h>

int count(int A,int B,int X){
  int X1 = A/X;
  int X2 = B/X;
  int n = X2 - X1;
  if(A%X == 0){
    n += 1;
  }
  return n;
}

int gcd(int x,int y){
  int z = 0;
  if(x%y == 0){
    z = y;
  }else{
    z = gcd(y,x%y);
  }
  return z;
}

int main(){
  int A,B,C,D;
  scanf("%d %d %d %d",&A,&B,&C,&D);
  int c = count(A,B,C);
  int d = count(A,B,D);
  int c_d = 0;
  int ans = 0;
  if(C < D){
    c_d = count(A,B,C*D/gcd(D,C));
  }else{
    c_d = count(A,B,C*D/gcd(C,D));
  }
  ans = (B-A+1)-c-d+c_d;
  printf("%d\n",ans);
  return 0;
}