// solutions need to be proved and have general ideas
#include <bits/stdc++.h>
constexpr int P = 1E9 + 7;
using i64 = long long;
// assume -P <= x < 2P
int norm(int x) {
if (x < 0) {
x += P;
}
if (x >= P) {
x -= P;
}
return x;
}
template<class T>
T power(T a, int b) {
T res = 1;
for (; b; b /= 2, a *= a) {
if (b % 2) {
res *= a;
}
}
return res;
}
struct Z {
int x;
Z(int x = 0) : x(norm(x)) {}
Z(i64 x) : x(norm(x % P)) {}
int val() const {
return x;
}
Z operator-() const {
return Z(norm(P - x));
}
Z inv() const {
assert(x != 0);
return power(*this, P - 2);
}
Z &operator*=(const Z &rhs) {
x = i64(x) * rhs.x % P;
return *this;
}
Z &operator+=(const Z &rhs) {
x = norm(x + rhs.x);
return *this;
}
Z &operator-=(const Z &rhs) {
x = norm(x - rhs.x);
return *this;
}
Z &operator/=(const Z &rhs) {
return *this *= rhs.inv();
}
friend Z operator*(const Z &lhs, const Z &rhs) {
Z res = lhs;
res *= rhs;
return res;
}
friend Z operator+(const Z &lhs, const Z &rhs) {
Z res = lhs;
res += rhs;
return res;
}
friend Z operator-(const Z &lhs, const Z &rhs) {
Z res = lhs;
res -= rhs;
return res;
}
friend Z operator/(const Z &lhs, const Z &rhs) {
Z res = lhs;
res /= rhs;
return res;
}
};
constexpr int N = 10000;
Z fac[N + 1], inv[N + 1];
Z nCk(int n, int k) {
if (n < k) {
return 0;
}
return fac[n] * inv[k] * inv[n - k];
}
int main() {
std::ios::sync_with_stdio(false);
std::cin.tie(nullptr);
fac[0] = inv[0] = 1;
for (int i = 1; i <= N; i++) {
fac[i] = fac[i - 1] * i;
inv[i] = 1 / fac[i];
}
int h, w;
std::cin >> h >> w;
std::vector dp(h + 3, std::vector<Z>(w + 3));
for (int i = 0; i <= w; i++) {
dp[0][i] = 1;
}
for (int i = 0; i <= h; i++) {
for (int j = 0; j <= w; j++) {
dp[i + 1][j] += dp[i][j];
dp[i + 1][j + 1] += nCk(j + 1, 1) * 4 * dp[i][j];
dp[i + 1][j + 2] += nCk(j + 2, 2) * dp[i][j];
dp[i + 2][j + 1] += nCk(i + 1, 1) * nCk(j + 1, 1) * dp[i][j];
}
}
std::cout << (dp[h][w] - 1).val() << "\n";
return 0;
}
