#include <iostream>
#include <string>
#include <cstring>
#include <cstdlib>
#include <cmath>
#include <algorithm>
#include <vector>
#include <set>
#include <map>
#include <queue>
#include <stack>
#include <list>
#include <iterator>
#include <cassert>
#include <numeric>
#include <functional>
#include <ctime>
#pragma warning(disable:4996) 

//#define ATCODER
#ifdef ATCODER
#include <atcoder/all>
#endif

typedef long long ll;
typedef unsigned long long ull;
#define LINF  9223300000000000000
#define LINF2 1223300000000000000
#define LINF3 1000000000000
#define INF 2140000000
const long long MOD = 1000000007;
//const long long MOD = 998244353;

using namespace std;
#ifdef ATCODER
using namespace atcoder;
#endif


const int max_comb = 410000;
vector<ll> fac(max_comb + 1); //n! (mod M)
vector<ll> ifac(max_comb + 1); //k!^(-1) (mod M)

ll mpow(ll x, ll n) { //x^n(mod M)
    ll ans = 1;
    while (n != 0) {
        if (n & 1) ans = ans * x % MOD;
        x = x * x % MOD;
        n = n >> 1;
    }
    return ans;
}

ll minv(ll x) {
    return mpow(x, MOD - 2);
}

ll comb(int a, int b) {     // C(a,b) = a! * b!^(-1) * (a-b)^(-1)
    if (a == 0 && b == 0)return 1;
    if (a < b || a < 0)return 0;
    ll tmp = ifac[a - b] * ifac[b] % MOD;
    return tmp * fac[a] % MOD;
}

ll perm(int a, int b) {     // P(a,b) = a! * (a-b)!^(-1)
    if (b == 0)return 1;
    if (a < b || a < 0)return 0;
    ll tmp = ifac[a - b] % MOD;
    return tmp * fac[a] % MOD;
}

void pre_comb()
{
    fac[0] = 1;
    ifac[0] = 1;
    for (int i = 0; i < max_comb; i++) {
        fac[i + 1] = fac[i] * (i + 1) % MOD; // n!(mod M)
        ifac[i + 1] = ifac[i] * minv(i + 1) % MOD; // k!^(-1) (mod M)
    }
    return;
}

void solve()
{    
    int h, w;
    scanf("%d%d", &h, &w);
    if (h == 1 || w == 1) {
        printf("0\n");
    }
    else {
        ll ans = (h + w - 3) * 2 % MOD;
        ans = ans * comb(h + w - 4, h - 2) % MOD;
        printf("%lld\n", ans);
    }

    return;
}

int main()
{
#if 0
    solve();
#else
    pre_comb();
    int T, t;
    scanf("%d", &T);
    for (t = 0; t < T; t++) {
        //printf("Case #%d: ", t + 1);
        solve();
    }
#endif
    return 0;
}