#include<algorithm>
#include<iostream>
#include<utility>
#include<cstring>
#include<vector>
#include<queue>
#include<set>
#define int long long
#define PB push_back
#define X first
#define Y second
using namespace std;
const int N=1e3+5,MOD=1e9+7;
int A[N]={},B[N]={};
int dp[N]={};
int vis[N]={};
int n;
signed main(){
    ios_base::sync_with_stdio(0),cin.tie(0),cout.tie(0);
    cin>>n;
    memset(dp,0x3f,sizeof(dp));
    for(int i=1;i<=n;i++) cin>>A[i];
    for(int i=1;i<=n;i++) cin>>B[i];
    dp[1]=B[1];
    for(int i=2;i<=n;i++) dp[i]=min(dp[i-1],dp[i-2])+B[i];
    //for(int i=1;i<=n;i++) cout<<dp[i]<<" \n"[i==n];
    vis[n]=dp[n];
    int now=n;
    while(now>1){
        if(dp[now-2]+B[now]==dp[now]) now-=2;
        else now-=1;
        vis[now]=dp[now];
    }
    //for(int i=1;i<=n;i++) cout<<vis[i]<<"\n";
    int ans=0;
    for(int i=1;i<=n;i++){
        if(vis[i]) ans=max(vis[i]+A[i],ans+A[i]);
        else ans+=A[i];
    }
    cout<<ans<<"\n";
    return 0;
}