#include <bits/stdc++.h>
#pragma GCC optimize("Ofast,no-stack-protector,unroll-loops,fast-math")
using namespace std;
const int N = 5000 + 10;
const int MOD = 1000000007;
const int LOG = 20;
const int INF = 1000000010;
const int delta = 11353;
int n, m, DP[N][N], T2[N];
inline int mul(int a, int b) { return a * 1ll * b % MOD; }
inline int add(int a, int b) {
  a += b;
  if (a >= MOD) a -= MOD;
  return a;
}
int32_t main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  cin >> n >> m;
  T2[0] = 1;
  for (int i = 1; i < N; i++) T2[i] = T2[i - 1] * 2ll % MOD;
  for (int i = 1; i <= m; i++) DP[1][i] = T2[i];
  for (int i = 2; i <= n; i++) {
    int sm = 0;
    for (int j = 1; j <= m; j++) {
      DP[i][j] = mul(DP[i - 1][j], j + 1);
      if (j > 1) {
        sm = mul(sm, 2);
        sm = add(sm, DP[i - 1][j - 1]);
        DP[i][j] = add(DP[i][j], sm);
      }
      cout << i << ' ' << j << ' ' << DP[i][j] << '\n';
    }
  }
  cout << DP[n][m];
  return 0;
}
