#include <bits/stdc++.h>
// #include <ext/pb_ds/assoc_container.hpp> 
// #include <ext/pb_ds/tree_policy.hpp>
 
using namespace std;
// using namespace __gnu_pbds;
typedef long long ll;
typedef long double ld;
 
typedef pair<ll, ll> pl;
typedef pair<ld,ld> pd;
typedef vector<ll> vl;
// typedef tree<ll, null_type, less<ll>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;
 
 
#define G(x) ll x; cin >> x;
#define F(i, l, r) for (ll i = l; i < (r); ++i)
#define all(a) begin(a), end(a)
#define K first
#define V second
#define OK(i,j) i >= 0 && i < n && j >= 0 && j < m
 
#define NN 2505
#define MM 5005
#define MOD 1000007

bool comp_three(string a, string b, string c) {
    bool ok = 1;
    for(ll i=0;i<4;i++) {
        if(a[i] == b[i] && a[i] == c[i]) continue;
        if(a[i] != b[i] && a[i] != c[i] && b[i] != c[i]) continue;
        ok = 0;
    }
    return ok;
}

void solve() {

    ll M, N;
    cin >> M >> N;

    ll numTop = M;
    ll numBottom = (N%2 == 0 ? M-1 : M);

    ll numEdgesTop = 2*numTop;
    ll numEdgesBottom = 2*numBottom;
    ll numEdgesSide = 2*(N+N-1);
    ll numHexagons = M*((N+1)/2) + (M-1)*(N/2);
    ll numEdges = (6*numHexagons + numEdgesTop + numEdgesBottom + numEdgesSide)/2;

    if(numHexagons%2 == 0) cout << numEdges - numHexagons/2 + 1 << '\n';
    else cout << numEdges - (numHexagons+1)/2 + 1 << '\n';

}

int main() {
    cin.tie(0)->sync_with_stdio(0);
    cout << fixed << setprecision(10);

    solve();

    return 0;

}