#include <fstream>
#define dim 102
using namespace std;

int x[dim],y[dim],P[dim];


int main()
{
    ifstream f("ieftin.in");
    ofstream g("ieftin.out");

int N,i,j;
f>>N;
for(i=1;i<=N;++i)
   f>>x[i];
for(i=1;i<N;++i)
   f>>y[i];

P[1]=x[1];
for(j=2;j<=N;++j)
{
    P[j]=P[j-1]+x[j];
    if(P[j]>P[j-2]+y[j-1])
       P[j]=P[j-2]+y[j-1];
}

g<<P[N]<<'\n';
    return 0;
}