(暴力枚举) $O(n^2)$
# include<iostream>
using namespace std;
int n,m,ans;
void dfs(int x,int y){
if(x==n&&y==m) ans++;
else{
//纵坐标没到边界,加1
if(y<m) dfs(x,y+1);
//横坐标没到边界,继续加1
if(x<n) dfs(x+1,y);
}
}
int main(){
cin>>n>>m;
dfs(0,0);
cout<<ans;
return 0;
}