#ifdef NACHIA
#define _GLIBCXX_DEBUG
#else
#define NDEBUG
#endif
#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
using i64 = long long;
using u64 = unsigned long long;
#define rep(i,n) for(int i=0; i<int(n); i++)
const i64 INF = 1001001001001001001;
template<typename A> void chmin(A& l, const A& r){ if(r < l) l = r; }
template<typename A> void chmax(A& l, const A& r){ if(l < r) l = r; }
#include <atcoder/modint>
using Modint = atcoder::static_modint<998244353>;
using namespace std;

void testcase(){
    int N; cin >> N;
    vector<i64> A(N), B(N), C(N);
    rep(i,N) cin >> A[i];
    rep(i,N) cin >> B[i];
    rep(i,N) cin >> C[i];
    vector<i64> D = A;
    i64 ans = 0;
    rep(t,2){
        vector<i64> dp(5);
        rep(i,N){
            dp[0] += A[i];
            dp[1] += B[i];
            dp[2] += C[i];
            dp[3] += B[i];
            dp[4] += A[i];
            rep(t,4) chmax(dp[t+1], dp[t]);
        }
        chmax(ans, dp[4]);
        swap(C, D);
    }
    cout << ans << endl;
}

int main(){
    ios::sync_with_stdio(false); cin.tie(nullptr);
    testcase();
    return 0;
}