#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <map>
#include <math.h>

#define ll long long

using namespace std;

enum {
    magic = 1000000007
};

ll my_mod(ll a, ll n) {
    return ((a % n) + n) % n;
}

template<typename T>
ostream &operator<<(ostream &out, vector<T> &v) {
    for (int i : v) {
        out << i << ' ';
    }
    out << '\n';
    return out;
}

template<typename T>
istream &operator>>(istream &in, vector<T> &v) {
    for (int i = 0; i < v.size(); ++i) {
        in >> v[i];
    }
    return in;
}

ll my_minys(ll s, ll a){
    if ((s-a)>0) return s-a;
    return 0;
}

ll ldp(ll n, ll k);

ll bdp(ll n, ll k) {
    if (n < 4 * k) {
        return ldp(n, k);
    }
    long long int t = n / k - 1;
    long long int s = bdp(n - t, k) /*+ t * k*/;
    long long int d0 = n-(n/k -1 )*k;
    long long int y = my_mod(s + t * (k) + (my_minys(s ,d0)) / (k - 1), n);
//    cout << "n:" << n << "  n/k-1:" << t << "      " << y << endl;
    return y;
}

ll ldp(ll n, ll k) {
    if (n == 1)
        return 0;
    return my_mod(ldp(n - 1, k) + k, n);
}


int main() {
    ll n, k;
    cin >> n >> k;
    cout << bdp(n, k)+1 << endl;
//    cout << ldp(n, k);
    return 0;
}