#include<bits/stdc++.h>
#define ll long long int
#define FOR(i,a,b) for(ll i=(ll)(a);i<(ll)(b);i++)
#define REP(i,n) FOR(i,0,n)
#define REP1(i,n) FOR(i,1,n)
using namespace std;

int main()
{
	int a,b,c,count;
	cin >> a >> b >> c;
	for(int i = a,i <= b,i++){
		if(i%c == 0)
			count++;
	}
	cout << count << "\n";
	return 0;
}