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>
typedef long long ll;
#define mod 1000000007
using namespace std;

int main() {
    ll a, b, c, d;
    cin >> a >> b >> c >> d;
    ll nc = b / c - (ll)(ceil((a / (double)c) - 0.0001)) + 1;
    ll nd = b / d - (ll)(ceil((a / (double)d) - 0.0001)) + 1;
    ll lcm = c * (d / __gcd(c, d));
    ll nlcm = b / lcm - (ll)(ceil((a / (double)lcm) - 0.0001)) + 1;
    cout << (b - a + 1) - (nc + nd - nlcm);
    return 0;
}