#include <bits/stdc++.h>
using namespace std;
typedef long long int ll;
 
int main() {
	// your code goes here
 
	ll n;
	cin>>n;
	ll arr1[n+1]={0},arr2[n+1]={0};
	ll i=1;
	while(i<=n)
	 {
	 	cin>>arr1[i];
	 	i++;
	 }
	 i=1;
	 while(i<=n)
	  {
	  	cin>>arr2[i];
	  	i++;
	  }
 
	  ll dp[n+1]={0};
	  ll k=0;
	  dp[1]=max(arr1[1],max(arr2[1],k));
	  dp[2]=max(dp[1],max(arr1[2],arr2[2]));
 
	  i=3;
	  while(i<=n)
	   {
	   	ll x= arr1[i]+dp[i-2];
	   	ll y = arr2[i]+dp[i-2];
	   	ll z = dp[i-1];
	   	dp[i]=max(x,max(y,z));  //trick to find max of 3 numbers
	   // cout<<i<<" "<<dp[i]<<"\n";
	   	i++;
	   }
	   cout<<dp[n];
	return 0;
}

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NQoyIDMgNCAtOCAyIAotNSA4IDMgMSAtNA==

5
2 3 4 -8 2 
-5 8 3 1 -4