#include <bits/stdc++.h>   using namespace std;   const long long MOD = 998244353;   long long dp[1010][2100][4];   int main() {     int n, k;     scanf( %d%d , &n, &k);     dp[1][1][0] = 1, dp[1][2][1] = 1, dp[1][2][2] = 1, dp[1][1][3] = 1;     for (int i = 2; i <= n; i++) {       for (int j = 1; j <= k; j++) {         dp[i][j][0] = (dp[i - 1][j][0] + dp[i - 1][j][1] + dp[i - 1][j][2] +                        dp[i - 1][j - 1][3]) %                       MOD;         dp[i][j][1] =             (dp[i - 1][j - 1][0] + dp[i - 1][j][1] + dp[i - 1][j - 1][3]) % MOD;         if (j >= 2) dp[i][j][1] = (dp[i][j][1] + dp[i - 1][j - 2][2]) % MOD;         dp[i][j][2] =             (dp[i - 1][j - 1][0] + dp[i - 1][j][2] + dp[i - 1][j - 1][3]) % MOD;         if (j >= 2) dp[i][j][2] = (dp[i][j][2] + dp[i - 1][j - 2][1]) % MOD;         dp[i][j][3] = (dp[i - 1][j - 1][0] + dp[i - 1][j][1] + dp[i - 1][j][2] +                        dp[i - 1][j][3]) %                       MOD;       }     }     printf( %lld n ,            (dp[n][k][0] + dp[n][k][1] + dp[n][k][2] + dp[n][k][3]) % MOD);   }   