#include "bits/stdc++.h"
using namespace std;
#define FOR(i,j,k) for(int (i)=(j);(i)<(int)(k);++(i))
#define rep(i,j) FOR(i,0,j)
#define each(x,y) for(auto &(x):(y))
#define mp make_pair
#define mt make_tuple
#define all(x) (x).begin(),(x).end()
#define debug(x) cout<<#x<<": "<<(x)<<endl
#define smax(x,y) (x)=max((x),(y))
#define smin(x,y) (x)=min((x),(y))
#define MEM(x,y) memset((x),(y),sizeof (x))
#define sz(x) (int)(x).size()
#define pb push_back
typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<ll> vll;

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    ll N, K;
    while(cin >> N >> K) {
        if(N <= K) {
            cout << 1 << endl;
            continue;
        }

        ll l = 0, r = N, m;
        while(r - l > 1) {
            m = (l + r) >> 1;
            ll x = N - m;
            ll y = x / K;
            (m > y ? r : l) = m;
        }
        cout << r << endl;
    }
}