#include <bits/stdc++.h>
using namespace std;
const long long mod = 1e9 + 7;
long long comb[2000][2000];
long long combi(long long n, long long r) {
  if (n < r || n < 0) return 0;
  if (comb[n][r] != 0) return comb[n][r];
  if (r == 0 || r == n) return comb[n][r] = 1;
  return comb[n][r] = (combi(n - 1, r - 1) + combi(n - 1, r)) % mod;
}
int main() {
  long long n, m;
  cin >> n >> m;
  for (int i = 0; i < 2000; i++) {
    for (int j = 0; j < 2000; j++) {
      comb[i][j] = 0;
    }
  }
  long long cnt = 0;
  for (long long i = 1; i <= n; i++) {
    long long a_cnt = combi(i + m - 1, m) - combi(i + m - 2, m);
    while (a_cnt < 0) a_cnt += mod;
    cnt += a_cnt % mod * combi(n - i + m, m) % mod;
    cnt %= mod;
  }
  cout << cnt << endl;
  return 0;
}
