#include<stdio.h>
int main()
{
    unsigned int a,b,x;
    int p=0,i;
    if(x>0){
    scanf("%u%u%u", &a,&b,&x);



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

}
