#include <bits/stdc++.h>
#define ll long long
#define MOD 1000000007
using namespace std;

ll mod(ll a, ll b) {
    return (b + a%b) % b;
}

ll exgcd(ll a, ll b, ll &x, ll &y) {
    if(a == 0) {
        x = 0, y = 1;
        return b;
    }
    ll xx, yy, g;
    g = exgcd(b%a, a, xx, yy);
    x = yy - xx*(b/a);
    y = xx;
    return g;
}

ll fact(ll N) {
    if (N == 0)
        return 1;
    else
        return ((N % MOD) * (fact(N - 1) % MOD)) % MOD;
}

int cnk(int n, int k) {
    ll a, b;
    exgcd(((fact(k) % MOD)* (fact(n - k) % MOD)) % MOD, MOD, a, b);
    return mod(fact(n) * a, MOD);
}

int main()
{
    int n, m;
    cin >> n >> m;
    cout << cnk(n + m, n) % MOD;
    return 0;
}