#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define rep(i, s, t) for (ll i = s; i < (ll)(t); i++)
#define all(x) begin(x), end(x)

template <class T> bool chmin(T& x, T y) {
	return x > y ? (x = y, true) : false;
}
template <class T> bool chmax(T& x, T y) {
	return x < y ? (x = y, true) : false;
}

struct io_setup {
	io_setup() {
		ios::sync_with_stdio(false);
		cin.tie(nullptr);
		cout << fixed << setprecision(15);
	}
} io_setup;

void solve() {
	ll n, m;
	cin >> n >> m;
	if (n == 1) {
		cout << "0\n";
		return;
	}
	if (n % 2 == 0) {
		cout << n * m << "\n";
		return;
	}
	ll ans = 0;
	int flg = 0;
	for (int sh = 31; sh >= 0; sh--) {
		if ((m >> sh) & 1) {
			ans += (n - 1) << sh;
			flg++;
		} else {
			ans += (flg / 2 * 2LL) << sh;
		}
	}
	cout << ans << "\n";
}

int main() {
	int t = 1;
	// cin >> t;
	while (t--) solve();
}