#include <bits/stdc++.h>
using namespace std;
using ll=long long;
using ull=unsigned long long;
using pll=pair<ll,ll>;
using tll=tuple<ll,ll,ll>;
using ld=long double;
const ll INF=(1ll<<60);
#define rep(i,n) for (ll i=0;i<(ll)(n);i++)
#define replr(i,l,r) for (ll i=(ll)(l);i<(ll)(r);i++)
#define all(v) v.begin(),v.end()
#define len(v) ((ll)v.size())
template<class T> inline bool chmin(T &a,T b){
    if(a>b){
        a=b;
        return true;
    }
    return false;
}
template<class T> inline bool chmax(T &a,T b){
    if(a<b){
        a=b;
        return true;
    }
    return false;
}
int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    ll n;
    cin >> n;
    vector<vector<ll>> v(3,vector<ll>(n));
    rep(i,3){
        rep(j,n){
            cin >> v[i][j];
        }
    }
    vector<vector<vector<ll>>> dp(n+1,vector<vector<ll>>(3,vector<ll>(3,-INF)));
    dp[0][0][0]=0;
    rep(i,n){
        rep(j,3){
            rep(k,3){
                
                replr(nj,j,min(3ll,j+2)){
                    replr(nk,k,min(3ll,k+2)){
                        ll x=v[0][i];
                        if((nj==1&&nk!=1)||(nj!=1&&nk==1)) x=v[1][i];
                        if(nj==1&&nk==1) x=v[2][i];
                        chmax(dp[i+1][nj][nk],dp[i][j][k]+x);
                    }
                }
            }
        }
    }
    ll ans=-INF;
    rep(i,3){
        rep(j,3){
            chmax(ans,dp[n][i][j]);
        }
    }
    cout << ans << '\n';
}