import java.io.*;
import java.util.*;
import java.util.stream.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner();
        int n = sc.nextInt();
        int[] reds = new int[n * 2];
        for (int i = 0; i < n * 2; i++) {
            reds[i] = sc.nextInt();
        }
        int[] blues = new int[n * 2];
        for (int i = 0; i < n * 2; i++) {
            blues[i] = sc.nextInt();
        }
        int[] sames = new int[n];
        for (int i = 0; i < n; i++) {
            sames[i] = sc.nextInt();
        }
        int[] diffs = new int[n];
        for (int i = 0; i < n; i++) {
            diffs[i] = sc.nextInt();
        }
        long[][] dp = new long[n * 2][2];
        dp[0][0] = reds[0];
        dp[0][1] = blues[0];
        for (int i = 1; i < n * 2; i++) {
            if (i % 2 == 0) {
                dp[i][0] = Math.max(dp[i - 1][0], dp[i - 1][1]) + reds[i];
                dp[i][1] = Math.max(dp[i - 1][0], dp[i - 1][1]) + blues[i];
            } else {
                dp[i][0] = Math.max(dp[i - 1][0] + sames[i / 2], dp[i - 1][1] + diffs[i / 2]) + reds[i];
                dp[i][1] = Math.max(dp[i - 1][0] + diffs[i / 2], dp[i - 1][1] + sames[i / 2]) + blues[i];
            }
        }
        System.out.println(Math.max(dp[n * 2 - 1][0], dp[n * 2 - 1][1]));
    }
}
class Utilities {
    static String arrayToLineString(Object[] arr) {
        return Arrays.stream(arr).map(x -> x.toString()).collect(Collectors.joining("\n"));
    }
    
    static String arrayToLineString(int[] arr) {
        return String.join("\n", Arrays.stream(arr).mapToObj(String::valueOf).toArray(String[]::new));
    }
}
class Scanner {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    StringTokenizer st = new StringTokenizer("");
    StringBuilder sb = new StringBuilder();
    
    public Scanner() throws Exception {
        
    }
    
    public int nextInt() throws Exception {
        return Integer.parseInt(next());
    }
    
    public long nextLong() throws Exception {
        return Long.parseLong(next());
    }
    
    public double nextDouble() throws Exception {
        return Double.parseDouble(next());
    }
    
    public int[] nextIntArray() throws Exception {
        return Stream.of(br.readLine().split(" ")).mapToInt(Integer::parseInt).toArray();
    }
    
    public String next() throws Exception {
        while (!st.hasMoreTokens()) {
            st = new StringTokenizer(br.readLine());
        }
        return st.nextToken();
    }
    
}