#include <bits/stdc++.h>
using namespace std;
#define int long long

#define dbg(x...) \
do { \
std::cout << #x << " -> "; \
err(x); \
} while (0)

void err() {
	std::cout << std::endl;
}

template<class T, class... Ts>
void err(T arg, Ts &... args) {
	std::cout << fixed << setprecision(10) << arg << ' ';
	err(args...);
}

void GENSHEN_START() {
	int n,m;cin >> n >> m;
	if (n > m) swap(n,m);
	if (n == 1) {
		int ans = 14 * (m / 4);
		if (m % 4 == 1) ans += 6;
		else if (m % 4 == 2) ans += 9;
		else if (m % 4 == 3) ans += 10;
		cout << ans;
		return ;
	}
	else {
		cout << n * m * 6;
	}
}	

signed main()
{
	ios::sync_with_stdio(false);cin.tie(nullptr);
	int T = 1;
	//cin >> T;
	while (T--) GENSHEN_START();
	return 0;
}