#include<stdio.h>
int main()
{
    unsigned int a,b;
     int x,i;
    long int p=0;

    scanf("%u%u%d", &a,&b,&x);


       for(i=a;i<=b;i++)
        {
            if(i%x==0)
            {
                p++;
            }
        }
    printf("%ld\n", p);
    return 0;

}
