#include <bits/stdc++.h>
using namespace std;
const long long MOD = 998244353;
long long dp[1005][2005][4], n;
long long go(int id, int colors, int prev) {
  if (id == n or colors < 0) return colors == 0;
  if (dp[id][colors][prev] != -1) return dp[id][colors][prev];
  long long ans = 0;
  if (prev < 2) {
    for (int i = 0; i < 4; i++)
      ans += go(id + 1, colors - (i != prev), i) % MOD;
  } else {
    for (int i = 0; i < 4; i++)
      ans += go(id + 1, colors - 2 * (i > 1 && i != prev), i) % MOD;
  }
  return dp[id][colors][prev] = ans;
}
int main() {
  long long k, ans = 0;
  scanf("%lld %lld", &n, &k);
  memset(dp, -1, sizeof(dp));
  ans += go(1, k - 1, 0) % MOD;
  ans += go(1, k - 1, 1) % MOD;
  ans += go(1, k - 2, 2) % MOD;
  ans += go(1, k - 2, 3) % MOD;
  printf("%lld\n", ans % MOD);
  return 0;
}
