#include<iostream>
using namespace std;
int main(){
    int a,b,c;
    cin >> a,b,c;
    int i = 0;
    
    for (int x=a; x<=b; x++){
        if (x % c == 0){
            i ++;
            
        }
    }
    cout <<i<<endl;
    
        
    }return 0;
}
