#include<bits/stdc++.h>
using namespace std;
 
int n,m,ans;
 
void dfs(int idx,int depth){
    if (depth == m){
        if (idx == 1) ans++;
        return;
    } 
    if (idx == n) dfs(1,depth+1);
    else dfs(idx+1,depth+1);
    if (idx == 1) dfs(n,depth+1);
    else dfs(idx-1,depth+1);
    return;
}
 
int main(){
    freopen("ballg.in","r",stdin);
    freopen("ballg.out","w",stdout);
    scanf("%d%d",&n,&m);
    dfs(1,0);
    cout<<ans;
    return 0;
}