#include <bits/stdc++.h>
using namespace std;
ifstream fin("INPUT.txt");
ofstream fout("OUTPUT.txt");
const int N = 21;
const int M = 20;
const long long INF = 1e18 + 1;
int mod = 1000000007;
int n, m, k, T;
int dp[N][N][N] = {0};
int DP(int s, int h, int t) {
  if (s == n && t == 2 * T - 1) return 1;
  if (s == n && t < 2 * T - 1 || t > 2 * T - 1) return 0;
  if (dp[s][h][t] != -1) return dp[s][h][t];
  int cnt = 0;
  for (int i = h - 1; i >= 1; i--) cnt += DP(s + 1, i, t + (t + 1) % 2);
  for (int i = h + 1; i <= 4; i++) cnt += DP(s + 1, i, t + t % 2);
  dp[s][h][t] = cnt;
  return cnt;
}
int main() {
  ios::sync_with_stdio(false);
  cout.precision(10);
  cin >> n >> T;
  for (int i = 0; i < N; (i++))
    for (int j = 0; j < N; (j++))
      for (int k = 0; k < N; (k++)) dp[i][j][k] = -1;
  int cnt = 0;
  for (int i = 1; i <= 4; i++)
    for (int j = i + 1; j <= 4; j++) cnt += DP(2, j, 0);
  cout << cnt << endl;
  return 0;
}
