#include<bits/stdc++.h>
using namespace std;
typedef pair<int, int> pii;
typedef long long int ll;


//4번 후보
//선택의 문제로 접근하면 된다.
int n, ans;
int a[1001];
int dp[1001][10001];
int f(int pos, int sum) {
    if (dp[pos][sum])
        return dp[pos][sum];
    
    if (pos > n)
        return 0;
    
    if (pos == n) {
        if (sum > ans)
            ans = sum;
        return ans;
    }
    int t = f(pos+2, sum+a[pos]);
    int tt = f(pos+1, sum);
    return dp[pos][sum] = max(t, tt);
    
    //return dp[pos][sum] = max(f(pos+2, sum+a[pos]),f(pos+1, sum));
    
}

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
 
    cin >> n;
    for (int i = 0; i < n; i++)
        cin >> a[i];
    
    cout << f(0, 0) << endl;
  
    return 0;
}