#include <iostream>
using namespace std;
int N,K,ar[1100][1100];
int main()
{
cin>>N>>K;
for(int n=1; n<=N+K-1; n++)
{
for(int k=1; k<=n; k++)
{
if(k==1) ar[n][k]=n;
else if(n==k) ar[n][k]=1;
else ar[n][k]=(ar[n-1][k-1]+ar[n-1][k])%1000000000;
}
}
cout<<ar[N+K-1][N];
}