#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define all(x) (x).begin(),(x).end()

typedef long long ll;
typedef pair<ll, ll> P;

const int mod =  1000000007;  //出力は (ans % mod + mod) % mod  (負の剰余を正にする)
const int inf = 1e9;
const long long INF = 1LL << 60;   // INF = 11

ll f(ll num){
    if(num == 1){
        return 1;;
    }else{
        return 2*f(num-1) + 1;
    }
}

int main()
{
    ll n,l; cin >> n >> l;
    ll x;
    if(n % l == 0){
        x = n/l;
    }else{
        x = n/l + 1;
    }
    cout << f(x) << endl;
}