#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pi pair<int,int>
#define pll pair<ll,ll>
#define ld  long double

const int INF = 1e9 + 7;

map<int , bool> visited;
void dfs(int start , int curr ,set<int> &possible){
    if(curr < 0) return;
    visited[start] = true;
    possible.insert(start);
    if(!visited.count(-start)){
        dfs(-start , curr - 1 , possible);
    }
    if(!visited.count(start - 1)){
        dfs(start - 1, curr - 2 , possible);
    }
}
void solve(){
    set<int> possible;
    ll B , C;
    cin >> B >> C;
    dfs(B , C , possible);
    cout << int(possible.size()) << endl;
    // cout << "the possible values " << endl;
    // for(auto t : possible)
    //  cout << t <<  " ";
    // cout << endl;
}

int main(){
    ios :: sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
    int tt = 1;

    for(int tc = 1; tc <= tt; tc++){
        // cout << "Case #" << tc << ": ";
        solve();
    }
}