#include <iostream>
#include <bits/stdc++.h>
using namespace std;
 
int main() {
	// your code goes here
 
	int n;
	cin>> n;
 
	vector<int> arr(n+1,0), brr(n+1, 0);
 
	for(int i=1; i<=n; i++){
		cin>>arr[i];
	}
	for(int i=1; i<=n; i++){
		cin>>brr[i];
	}
 
	vector<int> dp(n,0);
 
	dp[1] = max(arr[1], brr[1]);
	if(n==1) return dp[1];
 
	dp[2] = max(arr[2], brr[2]);
	if(n==2) return max(dp[1], dp[2]);
 
	dp[3] = max({dp[1], dp[2], dp[1]+arr[3], dp[1] + brr[3]});
 
	int i=4;
 
	while(i<=n){
 
		dp[i] = max({arr[i]+dp[i-2], brr[i]+dp[i-2], dp[i-1], dp[i-2]});
 
		i++;
	}
 
	cout<< dp[n];
 
	return 0;
}

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