import java.util.*;
class PrintNoFactor{
public static void main(String args[]){
Scanner sc = new Scanner(System.in);
int a = sc.nextInt();
int b = sc.nextInt();
int c = sc.nextInt();
int counter=0;
for(int i=a; i<=b; i++){
if(i%c == 0){
counter++;
}
}
System.out.println(counter);
}
}