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: Wrong Answer)

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <limits.h>


int main()
{
        int souwa;
        int  inputc;
        char numbuff[100000+1];
        long long int numbers[1000];
        int numnum;
        long long int i,j;
        long long int A, B, C, D;

        j = 0;

        numnum = 0;
        j = 0;
        while( (inputc = getc(stdin)) != EOF ) {
                if( inputc == ' ' || inputc == '\n' ) {
                        numbuff[j]  = '\0';
                        numbers[numnum++] = atoll(numbuff);
                        j=0;
                        continue;
                }
                else {
                        numbuff[j++] = inputc;
                }
        }
#ifdef DBG
        for( int k =0; k < numnum; k++ ) { printf("<%lld>", numbers[k]); } printf("\n");
        printf("get numbuff\n");
#endif

        A = numbers[0];
        B = numbers[1];
        C = numbers[2];
        D = numbers[3];
#ifdef DBG
        printf("%lld\n", LLONG_MAX );
        printf("A=%lld B=%lld C=%lld D=%lld\n", A, B, C, D);
#endif

        long long int count = 0;
        for( i = A; i < B; i++ ) {
                if( i % C !=0 && i % D !=0 ) {
                        count++;
                }
        }
        printf("%lld\n", count );
        return 0;
}