#include <bits/stdc++.h>   using namespace std;   long long dp[1001][2 * 1001][2];   long long MOD = 998244353;   int main() {     ios_base::sync_with_stdio(false);     int n, k;     cin >> n >> k;     dp[1][1][0] = 2;     dp[1][2][0] = 0;     dp[1][1][1] = 0;     dp[1][2][1] = 2;     for (int i = 2; i <= n; ++i) {       for (int j = 1; j <= min(2 * n, k); ++j) {         dp[i][j][0] = dp[i - 1][j][0] + dp[i - 1][j - 1][0] + dp[i - 1][j][1] * 2;         dp[i][j][0] %= MOD;         dp[i][j][1] =             dp[i - 1][j][1] + dp[i - 1][j - 2][1] + dp[i - 1][j - 1][0] * 2;         dp[i][j][1] %= MOD;       }     }     cout << (dp[n][k][0] + dp[n][k][1]) % MOD <<   n ;   }   