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++14 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <iostream>
#include <algorithm>
#include <string>
#include <vector>
#include <set>
#include <cmath>
#include <list>
#include <numeric>
#include <stack>
#include <queue>
#include <tuple>
#include <bitset>
#include <map>
#include <math.h>
using namespace std;
#define rep(i,n) for(int i = 0; i < n; i++)
typedef long long ll;
typedef pair<int,int> P;
const int inf = 1012345678;
int dx[] = {1,-1,0,0};
int dy[] = {0,0,1,-1};

float a;
float b;
float cd;

int main(){
  float A,B,C,D;
  cin >> A >> B >> C >>D;
  float ans = 0;
  a = A/C;
  b = B/C;
  if(floor(a) == a) ans += floor(b) - a + 1;
  else ans += floor(b) - ceil(a);
  
  a = A/D;
  b = B/D;
  if(floor(a) == a) ans += floor(b) - a + 1;
  else ans += floor(b) - ceil(a);
  
  a = A/(D*C);
  b = B/(D*C);
  if(floor(a) == a) ans -= floor(b) - a + 1;
  else ans -= floor(b) - ceil(a);
  
  cout << (B-A+1) - ans << endl;
}