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>
#include <stdint.h>
#include <inttypes.h>
#include <stdlib.h>

#define MIN(a,b) ((a)<(b)?(a):(b))
#define MAX(a,b) ((a)>(b)?(a):(b))
#define ABS(a) ((a)>(0)?(a):-(a))


typedef unsigned long long int uint64;
typedef long long int          int64;


void get_abcd (int64 *a, int64 *b,int64 *c,int64 *d)
{
  int cnt;
  
  cnt = scanf("%lld %lld %lld %lld", a, b, c, d);

  return;
}

int64 gcd(int64 a,int64 b){int64 c;while(b!=0){c=a%b;a=b;b=c;}return a;}
int64 lcm(int64 a,int64 b){int64 c=gcd(a,b);a/=c;return a*b;};

int main()
{
  int64 A, B, C, D;
  int64 i;
  int64 num = 0;
  int64 min, max;
  int64 min_num = 0;
  int64 max_num = 0;
  int64 lcm_num = 0;
  int64 lcm_val;

  get_abcd(&A, &B, &C, &D);

  min = MIN(C, D);
  max = MAX(C, D);

  min_num = B/min - ((A-1)/min);
  max_num = B/max - ((A-1)/max);
  lcm_val = lcm(min, max);
  lcm_num = B/lcm_val - ((A-1)/lcm_val);

  num = (B - A + 1);
  num -= min_num;
  num -= max_num;
  num += lcm_num;

  printf("%lld", num);

  return 0;
}