#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef vector<int> vint;
typedef pair<int,int> pint;
typedef vector<pint> vpint;
#define rep(i,n) for(int i=0;i<(n);i++)
#define reps(i,f,n) for(int i=(f);i<(n);i++)
#define each(it,v) for(__typeof((v).begin()) it=(v).begin();it!=(v).end();it++)
#define all(v) (v).begin(),(v).end()
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define chmax(a, b) a = (((a)<(b)) ? (b) : (a))
#define chmin(a, b) a = (((a)>(b)) ? (b) : (a))
const int MOD = 1e9 + 7;
const int INF = 1e9;

int main(void){
	ll n, k; cin >> n >> k;
	ll l = 1, r = n;
	while(r - l > 1){
		ll mid = (l + r) / 2;
		ll d = n - mid;//nokori
		ll cnt = d / (mid + 1);
		if(k <= cnt) l = mid; //もっとダメージ与える
		else r = mid;
	}
	while(1){
		ll d = n - l;
		ll cnt = d / l;
		if(cnt >= k) l++;
		else break;
	}
	printf("%lld\n", l);
	return 0;
}