#include<bits/stdc++.h>
#include<atcoder/all>
using namespace std;
using namespace atcoder;
using ll = long long;
using db = long double;
using ch = char;
using bl = bool;
using st = string;
using pll = pair<ll,ll>;
using psl = pair<st,ll>;
using vst = vector<st>;
using vch = vector<ch>;
using vvch = vector<vch>;
using vbl = vector<bl>;
using vvbl = vector<vbl>;
using vdb = vector<db>;
using vpll = vector<pll>;
using vvpll = vector<vpll>;
using vpsl = vector<psl>;
using vi = vector<int>;
using vvi = vector<vi>;
using vvvi = vector<vvi>;
using vvvvi = vector<vvvi>;
using vll = vector<ll>;
using vvll = vector<vll>;
using vvvll = vector<vvll>;
using vvvvll = vector<vvvll>;
using vvvvvll = vector<vvvvll>;
#define all(A) A.begin(),A.end()
#define rep(i, n) for (ll i = 0; i < (ll)(n); i++)
#define rrep(i,a,b) for(ll i=(ll)(a);i<=(ll)(b);i++)
#define drep(i,n) for(ll i=(ll)n-1; i>=0; i--)
#define drrep(i,a,b) for(ll i=(ll)a; i>=(ll)b; i--)

using mint = modint998244353;
// using mint = modint1000000007;
using vm = vector<mint>;
using vvm = vector<vm>; 
using vvvm = vector<vvm>;

const ll mod = 998244353;
const ll INF = 3e18;

template<class T> inline bool chmin(T &a, T b)
{
	if (a>b)
	{
		a=b;
		return true;
	}
	return false;
}

template<class T> inline bool chmax(T &a, T b)
{
	if (a<b)
	{
		a=b;
		return true;
	}
	return false;
}

ll gcd(ll a, ll b)
{
	if (a==0)return b;
	if (b==0)return a;
	ll c=a;
	while(a%b!=0)
	{
		c=a%b;
		a=b;
		b=c;
	}
	return b;
}

ll lcm(ll a,ll b){
	return a/gcd(a,b)*b;
}

ll Pow(ll a, ll n)
{
	ll res=1;
	while(n>0)
	{
		if(n%2==1)res*=a;
		a*=a;
		n/=2;
	}
	return res;
}

ll Pow(ll a, ll n, ll p)
{
	ll res=1;
	while(n>0)
	{
		a%=p;
		if(n%2==1)res*=a;
		a*=a;
		res%=p;
		n/=2;
	}
	return res;
}

void yn(bl ok)
{
	cout << (ok?"Yes":"No") << endl;
	return;
}

ll H,A;

int main()
{
	cin>>H>>A;
	ll cnt=0;
	while(H>0)
	{
		H/=A;
		cnt++;
	}
	cout << Pow(2,cnt)-1 << endl;
	return 0;
}