#include <bits/stdc++.h>
using namespace std;
const int oo = (int)1e9;
const double PI = 2 * acos(0);
const double eps = 1e-9;
inline int comp(const double &a, const double &b) {
  if (fabs(a - b) < eps) return 0;
  return a > b ? 1 : -1;
}
int di[] = {1, -1, 0, 0, 1, -1, 1, -1};
int dj[] = {0, 0, 1, -1, 1, -1, -1, 1};
int diK[] = {-2, -2, -1, 1, 2, 2, 1, -1};
int djK[] = {-1, 1, 2, 2, 1, -1, -2, -2};
int I, J;
inline bool val(const int &i, const int &j) {
  if (i < 0 || j < 0 || i >= I || j >= J) return false;
  return true;
}
int n;
long long dp[20][4][4][11][10];
long long calc(int ind, int p1, int p2, int r1, int r2) {
  if (r1 < 0 || r2 < 0) return 0;
  if (ind == n) {
    if (r1 || r2) return 0;
    return 1;
  }
  if (dp[ind][p1][p2][r1][r2] != -1) return dp[ind][p1][p2][r1][r2];
  long long ret = 0;
  for (int i = 0; i < (int)(4); i++) {
    if (i == p2) continue;
    if (p1 < p2 && p2 > i)
      ret += calc(ind + 1, p2, i, r1 - 1, r2);
    else if (p1 > p2 && p2 < i)
      ret += calc(ind + 1, p2, i, r1, r2 - 1);
    else
      ret += calc(ind + 1, p2, i, r1, r2);
  }
  return dp[ind][p1][p2][r1][r2] = ret;
}
int main() {
  int t;
  cin >> n >> t;
  memset(dp, -1, sizeof(dp));
  long long ret = 0;
  for (int i = 0; i < (int)(4); i++)
    for (int j = 0; j < (int)(4); j++)
      if (i != j) ret += calc(2, i, j, t, t - 1);
  cout << ret << endl;
  return 0;
}
