#include<bits/stdc++.h>
using namespace std;
#define int unsigned long long
signed main(){
	int h,a;
	cin >> h >> a;
	vector<int> b;
	while(true){
		if(h == 0) break;
		b.push_back(h);
		h /= a;
	}
	int c = (int)b.size();
	vector<int> d(c);
	int k = 1;
	for(int i = 0;i < c;i++){
		d[i] = k;
		k *= 2;
	}
	int ans = 0;
	for(int i = 0;i < c;i++){
		ans +=  d[i];
	}
	cout << ans << endl;
	
}