#include <bits/stdc++.h>
using namespace std;
long long int memo[22][5][5][12][11];
int N, T;
long long int solve(int idx, int prev_h, int curr_h, int humps, int dip) {
  if (idx == N - 1) {
    if (humps == T && dip == T - 1)
      return 1;
    else
      return 0;
  }
  if (humps > T || dip > T - 1) return 0;
  if (memo[idx][prev_h][curr_h][humps][dip] != -1)
    return memo[idx][prev_h][curr_h][humps][dip];
  long long int ways = 0;
  for (int i = 1; i <= 4; i++) {
    if (i == curr_h) continue;
    ways += solve(
        idx + 1, curr_h, i,
        (prev_h < curr_h && curr_h > i && prev_h != 0 ? humps + 1 : humps),
        (prev_h > curr_h && curr_h < i && prev_h != 0 ? dip + 1 : dip));
  }
  return memo[idx][prev_h][curr_h][humps][dip] = ways;
}
int main() {
  int cases = 1;
  while (cases--) {
    scanf("%d %d", &N, &T);
    for (int i = 0; i < N; i++)
      for (int j = 0; j <= 4; j++)
        for (int k = 0; k <= 4; k++)
          for (int x = 0; x < T + 1; x++)
            for (int y = 0; y < T; y++) memo[i][j][k][x][y] = -1;
    long long int ans = 0;
    for (int h = 1; h <= 4; h++) ans += solve(0, 0, h, 0, 0);
    cout << ans << endl;
  }
  return 0;
}
