#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <cstdio>
#include <cstring>
#include <cmath>
using namespace std;
using ll = long long;

constexpr int P = 1000000007;

int main() {
    int n, m;
    cin >> n >> m;

    int k = m - n + 1;
    vector<int> x(k);
    x[1] = 1;
    for (int i = 2; i < k; i++) {
        x[i] = P - (P / i * (ll)x[P % i] % P);
    }

    ll t = 1, s = t;
    for (int i = 1; i < k; i++) {
        t = t * (i + n) % P * x[i] % P;
        s += t;
        if (s >= P) s -= P;
    }

    cout << s << endl;

    return 0;
}