/* -*- coding: utf-8 -*-
 *
 * 3254.cc:  No.3254 Xor, Max and Sum - yukicoder
 */

#include<cstdio>
#include<algorithm>

using namespace std;

/* constant */

const int BN = 30;

/* typedef */

using ll = long long;

/* global variables */

/* subroutines */

/* main */

int main() {
  int n, m;
  scanf("%d%d", &n, &m);

  if (n == 1) { puts("0"); return 0; }
  if (! (n & 1)) { printf("%lld\n", (ll)m * n); return 0; }

  int as[3] = {};
  for (int i = BN - 1, bi = 1 << i; i >= 0; i--, bi >>= 1)
    if (bi <= m) {
      if (as[0] == 0) as[0] = as[1] = bi;
      else if (as[2] == 0 && (as[0] | bi) <= m) as[0] |= bi, as[2] = bi;
      else if ((as[1] | bi) <= m) as[1] |= bi, as[2] |= bi;
    }
  //printf(" %d %d %d\n", as[0], as[1], as[2]);

  ll s = (ll)m * (n - 3) + as[0] + as[1] + as[2];
  printf("%lld\n", s);

  return 0;
}