#include<iostream>
#include<iomanip>
#include<algorithm>
#include<cstring>
#include<string>
#include<cmath>
#include<vector>
#include<queue>
#include<stack>
#include<map>
#include<set>
using namespace std;
const int inf=1e9,dx[]={-1,0,1,0},dy[]={0,-1,0,1};
int n,a[3][100],ans,x,y;
int main(){
	cin>>n;
	for(int i=1;i<=2;i++)
		for(int j=1;j<=n;j++)
			cin>>a[i][j];
	ans=a[1][1];
	x=y=1;
	for(int i=1;i<=n;i++)
	{
		if(x==1)
		{
			if(a[x+1][y]>a[x][y+1])
			{
				ans+=a[x+1][y];
				x++;
			}
			else
			{
				ans+=a[x][y+1];
				y++;
			}
		}
		else
			ans+=a[x][y+1],y++;
	}
	cout<<ans;
	return 0;
}