//TLE
//全探索
//小さなケースでの確認用

#include <iostream>
#include <vector>
#include <cstdio>
#include <sstream>
#include <map>
#include <string>
#include <algorithm>
#include <queue>
#include <cmath>
#include <set>
using namespace std;

#define MOD 1000000007

int main(){
	long long a,b;
	cin >> a >> b;
	int P;
	cin >> P;

	long long ans = 0;
	char baff[100];

	for(long long i=a; i<=b; i++){
		bool ok = false;
		if(i%3==0) ok = true;
		sprintf(baff, "%lld", i);
		string s(baff);
		if(s.find('3') != string::npos) ok = true;
		if(i%P == 0) ok = false;

		if(ok) ans++;
	}
	cout << ans << endl;

	return 0;
}