#include <bits/stdc++.h>
using namespace std;
using ll = long long;
extern const ll MOD;
const int MAX = 500000;

ll fac[MAX], finv[MAX], inv[MAX];

void COMinit() {
    fac[0] = fac[1] = 1;
    finv[0] = finv[1] = 1;
    inv[1] = 1;
    for (int i = 2; i < MAX; i++){
        fac[i] = fac[i - 1] * i % MOD;
        inv[i] = MOD - inv[MOD%i] * (MOD / i) % MOD;
        finv[i] = finv[i - 1] * inv[i] % MOD;
    }
}

// 二項係数計算
ll COM(int n, int k){
    if (n < k) return 0;
    if (n < 0 || k < 0) return 0;
    return fac[n] * (finv[k] * finv[n - k] % MOD) % MOD;
}

ll Expo(ll N,ll K,ll md = MOD) {
    if (md == 0) {
        ll sum = 1;
        for (int i = 0; i < K; i++) sum *= N;
        return sum;
    }
    if (md == 1) return 0;
    N %= md;
    if (K == 0) {
        return 1;
    }
    ll Kc = K,rui = N,ans = 1;
    while(Kc) {
        if (Kc % 2) {
            ans *= rui;
            ans %= md;
        }
        rui *= rui;
        rui %= md;
        Kc /= 2;
    }
    return ans;
}

const ll MOD = 1e9+7;

int main(){
    COMinit();
    ll N, K;
    cin >> N >> K;
    ll sum = 1;
    for (ll i = 1; i <= N; i++) {
        sum *= K - i + 1;
        sum %= MOD;
        sum *= Expo(i, MOD - 2);
        sum %= MOD;
    }
    if (K < N) sum = 0;
    ll ans = 0;
    bool flag = false;
    for (ll i = 0; i <= N; i++) {
        ans += sum * COM(N - 1, i) % MOD;
        ans %= MOD;
        if (flag || N <= K) {
            sum *= K + i + 1;
            sum %= MOD;
            sum *= Expo(K - N + i + 1, MOD - 2);
            sum %= MOD;
        }
        else if (K + i + 1 == N && !flag) {
            flag = true;
            sum = 1;
        }
    }
    cout << ans << endl;
    return 0;
}