/* package whatever; // don't place package name! */
 
import java.util.*;
import java.lang.*;
import java.io.*;
 
/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
		// your code goes here
		Scanner sc=new Scanner(System.in);
		int n=sc.nextInt();
		int a[]=new int[n+1];
		int b[]=new int[n+1];
 
		for(int i=1;i<=n;i++)
		a[i]=sc.nextInt();
 
		for(int i=1;i<=n;i++)
		b[i]=sc.nextInt();
 
		int dp[]=new int[n+1];
 
		dp[1]=Math.max(a[1],b[1]);
		dp[2]=Math.max(a[2],b[2]);
		for(int i=3;i<=n;i++)
		{
			dp[i]=Math.max(Math.max(a[i],b[i])+dp[i-2],dp[i-1]);
		}
 
		System.out.println(dp[n]);
 
	}
}

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