#include <bits/stdc++.h>
using namespace std;
int dp[20 + 10][5][5][11][11], n, t;
bool v[20 + 10][5][5][11][11];
int solve(int idx, int pp, int p, int ups, int dwns) {
  if (p < 1 || p > 4 || ups > t || idx > n) return 0;
  if (idx == n && ups == t && dwns == t - 1) return 1;
  if (idx == n) return 0;
  if (v[idx][pp][p][ups][dwns]) return dp[idx][pp][p][ups][dwns];
  if (pp < p)
    dp[idx][pp][p][ups][dwns] += solve(idx + 1, p, p + 1, ups, dwns) +
                                 solve(idx + 1, p, p + 2, ups, dwns) +
                                 solve(idx + 1, p, p + 3, ups, dwns);
  if (pp < p)
    dp[idx][pp][p][ups][dwns] += solve(idx + 1, p, p - 1, ups + 1, dwns) +
                                 solve(idx + 1, p, p - 2, ups + 1, dwns) +
                                 solve(idx + 1, p, p - 3, ups + 1, dwns);
  if (pp > p)
    dp[idx][pp][p][ups][dwns] += solve(idx + 1, p, p + 1, ups, dwns + 1) +
                                 solve(idx + 1, p, p + 2, ups, dwns + 1) +
                                 solve(idx + 1, p, p + 3, ups, dwns + 1);
  if (pp > p)
    dp[idx][pp][p][ups][dwns] += solve(idx + 1, p, p - 1, ups, dwns) +
                                 solve(idx + 1, p, p - 2, ups, dwns) +
                                 solve(idx + 1, p, p - 3, ups, dwns);
  v[idx][pp][p][ups][dwns] = true;
  return dp[idx][pp][p][ups][dwns];
}
int main() {
  ios::sync_with_stdio(false), cin.tie(0);
  int x = 0;
  cin >> n >> t;
  for (int i = 1; i <= 4; i++)
    for (int j = 1; j <= 4; j++)
      if (i == j)
        continue;
      else
        x += solve(2, i, j, 0, 0);
  cout << x << endl;
  return 0;
}
