#include <bits/stdc++.h>
using namespace std;

pair<long long, long long> range(long long b, long long c) {
    long long n = c / 2;
    if (c % 2 == 0) {
        if (c == 0) return {b, b};
        else return {b - n, b + n - 1};
    } else {
        return {-b - n, -b + n};
    }
}

int main() {
    long long b, c;
    cin >> b >> c;
    auto [l1, r1] = range(b, c);
    auto [l2, r2] = range(b, c - 1);
    long long ans = (r1 - l1 + 1) + (r2 - l2 + 1) - max(0LL, min(r1, r2) - max(l1, l2) + 1);
    cout << ans << '\n';
}
#include <bits/stdc++.h>
using namespace std;
//using namespace atcoder;
struct fast_ios { fast_ios(){ cin.tie(0); ios::sync_with_stdio(false); cout << fixed << setprecision(20); }; } fast_ios_;
#define FOR(i, begin, end) for(int i=(begin);i<(end);i++)
#define REP(i, n) FOR(i,0,n)
#define IFOR(i, begin, end) for(int i=(end)-1;i>=(begin);i--)
#define IREP(i, n) IFOR(i,0,n)
#define Sort(v) sort(v.begin(), v.end())
#define Reverse(v) reverse(v.begin(), v.end())
#define all(v) v.begin(),v.end()
#define SZ(v) ((int)v.size())
#define Lower_bound(v, x) distance(v.begin(), lower_bound(v.begin(), v.end(), x))
#define Upper_bound(v, x) distance(v.begin(), upper_bound(v.begin(), v.end(), x))
#define chmax(a, b) a = max(a, b)
#define chmin(a, b) a = min(a, b)
#define bit(n) (1LL<<(n))
#define debug(x) cout << #x << "=" << x << endl;
#define vdebug(v) { cout << #v << "=" << endl; REP(i_debug, v.size()){ cout << v[i_debug] << ","; } cout << endl; }
#define mdebug(m) { cout << #m << "=" << endl; REP(i_debug, m.size()){ REP(j_debug, m[i_debug].size()){ cout << m[i_debug][j_debug] << ","; } cout << endl;} }
#define pb push_back
#define fi first
#define se second
#define int long long
#define INF 1000000000000000000
template<typename T> istream &operator>>(istream &is, vector<T> &v){ for (auto &x : v) is >> x; return is; }
template<typename T> ostream &operator<<(ostream &os, vector<T> &v){ for(int i = 0; i < v.size(); i++) { cout << v[i]; if(i != v.size() - 1) cout << endl; }; return os; }
template<typename T1, typename T2> ostream &operator<<(ostream &os, pair<T1, T2> p){ cout << '(' << p.first << ',' << p.second << ')'; return os; }
template<typename T> void Out(T x) { cout << x << endl; }
template<typename T1, typename T2> void chOut(bool f, T1 y, T2 n) { if(f) Out(y); else Out(n); }

using vec = vector<int>;
using mat = vector<vec>;
using Pii = pair<int, int>;
using v_bool = vector<bool>;
using v_Pii = vector<Pii>;

//int dx[4] = {1,0,-1,0};
//int dy[4] = {0,1,0,-1};
//char d[4] = {'D','R','U','L'};

const int mod = 1000000007;
//const int mod = 998244353;



signed main(){

    int B, C; cin >> B >> C;
    int ans = 0;
    if(B > 0){
        //[-B,B]
        if(C >= 2 * B) ans++;
        ans += min(B, C / 2 + 1);
        ans += min(B, (C - 1) / 2 + 1);
        //(-INF,-B)
        ans += (C - 1) / 2;
        //(B,INF)
        if(C >= 4) ans += (C - 4) / 2 + 1;
    }else if(B < 0){
        //(-INF,B]
        ans += C / 2 + 1;
        //[-B,INF)
        ans += (C - 1) / 2 + 1;
        //(B,-B)
        if(C >= 2 * (-B) + 1) ans++;
        ans += min(-B - 1, (C - 1) / 2);
        if(C >= 2) ans += min(-B - 1, (C - 2) / 2);

    }else if(B == 0){
        ans += C / 2 + 1;
        ans += (C - 1) / 2;
    }
    Out(ans);

    return 0;
}
