#include <iostream>

using namespace std;

int main(){
    int N;
    cin >> N;
    int l1, l2 ;
    cin >> l1;
    l2 = l1;

    for(int i=1; i<N; i++){
        int t;
        cin >> t;
        if(l2 + t < l1 +t){
            t += l2;
        }else{
            t += l1;
        }
        l2 = l1; l1 = t;
    }

    cout << l1 << endl;

    return 0;
}