#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int MOD = (int)1e9;

ll N,M,W,H;
int combination_mod(int n, int m, int s=0){
    static vector<vector<int> > c;
    if(n<0||m<0||n<m)return 0;
    m=min(m,n-m);
    if((int)c.size()<=n)c.resize(n+1);
    if((int)c[n].size()==0) c[n].resize(n/2+1);
    if(c[n][m]!=0) return c[n][m];
    int res;
    if(n==0||m==0)res=1; else if(m==1)res=n;
    else res=(combination_mod(n-1,m,s+1)+combination_mod(n-1,m-1,s+1))%MOD;
    return(c[n][m]=res);
}

int main(){
    cin >> N >> M;
    N -= N/1000/M*1000*M;
    N = N/1000;

    cout << combination_mod(M,N) << endl;
}