#include <bits/stdc++.h>
using namespace std;
const int inf = 999999999;
const int maxn = 1100;
const long long mod = 998244353;
long long dp[maxn][2 * maxn][2], n, m;
int main() {
  int i, j;
  memset(dp, 0, sizeof(dp));
  cin >> n >> m;
  dp[1][2][1] = 2;
  dp[1][1][0] = 2;
  for (i = 2; i <= n; i++) {
    for (j = 1; j <= m; j++) {
      dp[i][j][0] +=
          2 * dp[i - 1][j][1] + dp[i - 1][j - 1][0] + dp[i - 1][j][0];
      dp[i][j][0] %= mod;
      dp[i][j][1] +=
          2 * dp[i - 1][j - 1][0] + dp[i - 1][j - 2][1] + dp[i - 1][j][1];
      dp[i][j][1] %= mod;
    }
  }
  long long ans = (dp[n][m][0] + dp[n][m][1]) % mod;
  cout << ans << endl;
  return 0;
}
