//
// Created by 16373 on 2024/11/13.
//
#include <bits/stdc++.h>
#define int long long
using namespace std;
const int mod=998244353;
int a[10];

void solve(){
    int n,m;
    cin>>n>>m;
    if(n>1 && m>1){
        cout<<6*m*n;
        return;
    }
    if(n==1 && m==1){
        cout<<6;
        return;
    }
    int row[4]={0,6,9,10};
    int col[4]={0,6,8,9};
    if(n==1){
        int cnt=m/4,md=m%4;
        int res=cnt*14+row[md];
        cout<<res;
        return;
    }
    if(m==1){
        int cnt=n/4,md=n%4;
        int res=cnt*14+col[md];
        cout<<res;
    }

}
signed main(){
    ios::sync_with_stdio(0); cin.tie(0);
    int t=1;
//    cin>>t;
    while(t--){
        solve();
    }
    return 0;
}
//2
//630
//3029 2336 377 41 10 61
//3000
//20000 10000 0 0 0 0