#include #define rep(i,n) for(int i=(0);i<(n);i++) using namespace std; typedef long long ll; typedef unsigned long long ull; template bool chmax(T &a, const T &b) { if (a bool chmin(T &a, const T &b) { if (a>b) { a=b; return 1; } return 0; } int main(){ cin.tie(0); ios::sync_with_stdio(false); ll n, m; cin >> n >> m; n /= 1000; n %= m; ll MOD = 1e9; int max_m = 10101; ll c[2][max_m]; rep(i, 2) rep(j, max_m) c[i][j] = 0; c[1][0] = c[1][1] = 1; for(int i = 2; i <= m; i++){ rep(j, max_m) c[i%2][j] = 0; c[i%2][0] = c[i%2][i] = 1; for(int j = 1; j <= i - 1; j++){ c[i%2][j] = c[(i-1)%2][j-1] + c[(i-1)%2][j]; c[i%2][j] %= MOD; } } cout << c[m%2][n] << endl; }