#include <iostream>
#include <vector>
#include <cmath>
#include <map>
#include <set>
#include <iomanip>
#include <queue>
#include <algorithm>
#include <numeric>
#include <deque>
#include <complex>
#include <cassert>

using namespace std;
using ll = long long;

int main(){

    ll N;
    cin >> N;
    vector<ll> A(2*N+1), B(2*N+1), X(2*N+1), Y(2*N+1);
    vector<vector<ll>> dp(2*N+1, vector<ll>(2));
    for (int i=1; i<=2*N; i++) cin >> A[i];
    for (int i=1; i<=2*N; i++) cin >> B[i];
    for (int i=1; i<=N; i++) cin >> X[i*2];
    for (int i=1; i<=N; i++) cin >> Y[i*2];

    dp[1][0] = A[1]; dp[1][1] = B[1];

    for (int i=2; i<=2*N; i++){
        dp[i][0] = max(dp[i-1][0] + X[i], dp[i-1][1] + Y[i]) + A[i];
        dp[i][1] = max(dp[i-1][0] + Y[i], dp[i-1][1] + X[i]) + B[i];
    }

    cout << max(dp[N*2][0], dp[N*2][1]) << endl;

    return 0;
}