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

#define CPP_STR(x) CPP_STR_I(x)
#define CPP_CAT(x, y) CPP_CAT_I(x, y)
#define CPP_STR_I(args...) #args
#define CPP_CAT_I(x, y) x##y

#define ASSERT(expr...) assert((expr))

using i8 = int8_t;
using u8 = uint8_t;
using i16 = int16_t;
using u16 = uint16_t;
using i32 = int32_t;
using u32 = uint32_t;
using i64 = int64_t;
using u64 = uint64_t;

using f32 = float;
using f64 = double;
// }}}

constexpr i64 INF = 1'010'000'000'000'000'017LL;

constexpr i64 MOD = 998244353LL;

constexpr f64 EPS = 1e-12;

constexpr f64 PI = 3.14159265358979323846;

#define M5 100007
#define M9 1000000000

#define F first
#define S second

// util {{{
#define FOR(i, start, end) for (i64 i = (start), CPP_CAT(i, xxxx_end) = (end); i < CPP_CAT(i, xxxx_end); ++i)
#define REP(i, n) FOR(i, 0, n)

#define all(x) (x).begin(), (x).end()
#define ll long long int
#define VI vector<ll>
#define VVI vector<VI>

#define ISD true
#define debug(x) \
    if (ISD)     \
    cout << #x << ": " << x << endl

template <typename T, typename U, typename Comp = less<>>
bool chmax(T &xmax, const U &x, Comp comp = {})
{
    if (comp(xmax, x))
    {
        xmax = x;
        return true;
    }
    return false;
}

template <typename T, typename U, typename Comp = less<>>
bool chmin(T &xmin, const U &x, Comp comp = {})
{
    if (comp(x, xmin))
    {
        xmin = x;
        return true;
    }
    return false;
}

int main()
{
    ll N;
    cin >> N;
    vector<ll> 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<vector<ll>> dp(N + 1, vector<ll>(5, -1));
    dp[0][0] = 0;
    auto dp2 = dp;
    REP(i, N)
    {
        REP(j, 5)
        {
            if (dp[i][j] == -1)
            {
                continue;
            }
            REP(k, 2)
            {
                if (j + k == 5)
                {
                    continue;
                }
                if ((j + k) % 2 == 0)
                {
                    chmax(dp[i + 1][j + k], dp[i][j] + A[i]);
                }
                else
                {
                    chmax(dp[i + 1][j + k], dp[i][j] + B[i]);
                }
            }
        }
    }

    REP(i, N)
    {
        REP(j, 5)
        {
            if (dp2[i][j] == -1)
            {
                continue;
            }
            REP(k, 2)
            {
                if (j + k == 5)
                {
                    continue;
                }
                if ((j + k) % 2 == 0)
                {
                    if (j + k == 2)
                    {
                        chmax(dp2[i + 1][j + k], dp2[i][j] + C[i]);
                    }
                    else
                    {
                        chmax(dp2[i + 1][j + k], dp2[i][j] + A[i]);
                    }
                }
                else
                {
                    chmax(dp2[i + 1][j + k], dp2[i][j] + B[i]);
                }
            }
        }
        if (dp2[i][0] != -1)
        {
            chmax(dp2[i + 1][2], dp2[i][0] + C[i]);
        }
        if (dp2[i][2] != -1)
        {
            chmax(dp2[i + 1][4], dp2[i][2] + A[i]);
        }
    }

    ll ans = 0;
    REP(i, 5)
    {
        chmax(ans, dp[N][i]);
        chmax(ans, dp2[N][i]);
    }
    cout << ans << endl;
}