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 <bits/stdc++.h>
#define ROOP(i, N) for(int i=0; i++; i<N)
#define RVROOP(i, N) for(int i=N; i--; i>=0)
#define INF 1e9
#define MOD 1000000007
#define ALL(v) v.begin(), v.end()
using namespace std;
typedef long long ll;
int main() {
  ll A,B,C,D; cin>>A>>B>>C>>D;
  ll p[3]={C,D,C*D},ans[3];
  for(int i=0; i<3; i++){
    ll a=A,b=B;
    if(A%p[i]!=0){
      a=A+p[i]-A%p[i];
    }
    if(B%p[i]!=0){
      b=B-B%p[i];
    }
    ans[i]=(b-a+1)/p[i]+1;
  }
  cout<<B-A+1-ans[0]-ans[1]+ans[2]<<endl;
}