#include <bits/stdc++.h> using namespace std; using ll = long long; #define ALL(obj) (obj).begin(),(obj).end() #define SPEED cin.tie(0);ios::sync_with_stdio(false); template<class T> using PQ = priority_queue<T>; template<class T> using PQR = priority_queue<T,vector<T>,greater<T>>; constexpr long long MOD = (long long)1e9 + 7; constexpr long long MOD2 = 998244353; constexpr long long HIGHINF = (long long)1e18; constexpr long long LOWINF = (long long)1e15; constexpr long double PI = 3.1415926535897932384626433L; template <class T> vector<T> multivector(size_t N,T init){return vector<T>(N,init);} template <class... T> auto multivector(size_t N,T... t){return vector<decltype(multivector(t...))>(N,multivector(t...));} template <class T> void corner(bool flg, T hoge) {if (flg) {cout << hoge << endl; exit(0);}} template <class T, class U>ostream &operator<<(ostream &o, const map<T, U>&obj) {o << "{"; for (auto &x : obj) o << " {" << x.first << " : " << x.second << "}" << ","; o << " }"; return o;} template <class T>ostream &operator<<(ostream &o, const set<T>&obj) {o << "{"; for (auto itr = obj.begin(); itr != obj.end(); ++itr) o << (itr != obj.begin() ? ", " : "") << *itr; o << "}"; return o;} template <class T>ostream &operator<<(ostream &o, const multiset<T>&obj) {o << "{"; for (auto itr = obj.begin(); itr != obj.end(); ++itr) o << (itr != obj.begin() ? ", " : "") << *itr; o << "}"; return o;} template <class T>ostream &operator<<(ostream &o, const vector<T>&obj) {o << "{"; for (int i = 0; i < (int)obj.size(); ++i)o << (i > 0 ? ", " : "") << obj[i]; o << "}"; return o;} template <class T, class U>ostream &operator<<(ostream &o, const pair<T, U>&obj) {o << "{" << obj.first << ", " << obj.second << "}"; return o;} template <template <class tmp> class T, class U> ostream &operator<<(ostream &o, const T<U> &obj) {o << "{"; for (auto itr = obj.begin(); itr != obj.end(); ++itr)o << (itr != obj.begin() ? ", " : "") << *itr; o << "}"; return o;} void print(void) {cout << endl;} template <class Head> void print(Head&& head) {cout << head;print();} template <class Head, class... Tail> void print(Head&& head, Tail&&... tail) {cout << head << " ";print(forward<Tail>(tail)...);} template <class T> void chmax(T& a, const T b){a=max(a,b);} template <class T> void chmin(T& a, const T b){a=min(a,b);} void YN(bool flg) {cout << (flg ? "YES" : "NO") << endl;} void Yn(bool flg) {cout << (flg ? "Yes" : "No") << endl;} void yn(bool flg) {cout << (flg ? "yes" : "no") << endl;} int main() { ll N,K,X,ans = 0; cin >> N >> K; if(N%2==0) { if(K%2==0) { ans++; X = 1; for(ll i = 0; i < K; i += 2) { X += 2; if(X > N) break; ans++; } X = N+1; for(ll i = 0; i < K; i += 2) { X -= 2; if(X < 1) break; ans++; } chmin(ans,N/2); } else { ans+=2; K--; X = 2; for(ll i = 0; i < K; i += 2) { X += 2; if(X > N) break; ans++; } X = N; for(ll i = 0; i < K; i += 2) { X -= 2; if(X < 1) break; ans++; } chmin(ans,N/2); } } else { if(K%2==0) { ans++; X = 1; for(ll i = 0; i < K; i += 2) { X += 2; if(X > N) break; ans++; } X = N+1; for(ll i = 0; i < K; i += 2) { X -= 2; if(X < 1) break; ans++; } } else { ans+=2; K--; X = 2; for(ll i = 0; i < K; i += 2) { X += 2; if(X > N) break; ans++; } X = N; for(ll i = 0; i < K; i += 2) { X -= 2; if(X < 1) break; ans++; } } } cout << ans << endl; return 0; }