#include <iostream>
#include <fstream>
#include <vector>
#include <cstring>
#include <string>
#include <algorithm>
#include <iomanip>
using namespace std;
typedef long long ll;
int main() {
	cin.tie(0);
	ios::sync_with_stdio(false);

	ll N, D;
	cin >> N >> D;

	if(N % D == 0) {
		cout << N / D - 1 << endl;
		return 0;
	}

	ll skip = D - N % D;
	ll ans = 0;
	ans += N / D * D / skip;

	ll rem = N % D;
	ans += rem / skip;

	cout << ans - 1 << endl;
}