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: Runtime Error)

#include<stdio.h>

int main(){

    long int A, B;
    int C, D;
    scanf("%ld%ld%d%d", &A, &B, &C, &D);

    long int pro = 0;
    for (int i = 0; i < D; i++){
        pro += C;
    }

    int LCM_CD;
    int a, b;
    int r = 1;

    if(C>D){
        a = C;
        b = D;
    }else{
        a = D;
        b = C;
    }

    while(r != 0){
        r = a % b;
        a = b;
        b = r;
    }

    LCM_CD = pro/b;

    long int nC, nD, nCD;

    nC = B / C - (A-1)/ C;
    nD = B / D - (A-1)/ D;
    nCD = B / LCM_CD - (A-1)/ LCM_CD;

    printf("%ld", (B - A + 1) - (nC + nD - nCD));

    return 0;
}