#include <bits/stdc++.h>
using namespace std;
#define FAST_IO ios::sync_with_stdio(false), cin.tie(0), cout.tie(0)
#define endl '\n'
#define ll long long
ll n, m;
void solve() {
	cin >> n >> m;
	ll row[] = {0, 6, 9, 10}, col[] = {0, 6, 8, 9};
	if((n >= 2 && m >=2) || (n == 1 && m == 1)) cout << 6 * n * m << endl;
	else if(n == 1) cout << m / 4 * 14 + row[m % 4] <<endl;
	else if(m == 1) cout << n / 4 * 14 + col[n % 4] << endl;
}
int main() {
#ifdef xrl
	freopen("in.txt", "r", stdin), freopen("out.txt", "w", stdout);
#endif
	FAST_IO;
	int _ = 1;
	//cin >> _;
	while(_ --) solve();
#ifdef xrl
	cout << "Time used = " << (double)(clock() * 1.0 / CLOCKS_PER_SEC) << "s";
#endif
	return 0;
}