#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

int main() {
    int N;
    cin >> N;
    vector<int> A(N);
    for (int i = 0; i < N; i++) {
        cin >> A[i];
    }
    
    vector<vector<int>> dp(N, vector<int>(N, 0));
    
    int maxSize = 0;
    for (int i = 0; i < N; i++) {
        dp[i][i] = A[i];
        maxSize = max(maxSize, A[i]);
    }
    
    for (int len = 2; len <= N; len++) {  
        for (int i = 0; i + len - 1 < N; i++) {
            int j = i + len - 1;
            
            for (int k = i; k < j; k++) {
                if (dp[i][k] && dp[k + 1][j] && dp[i][k] == dp[k + 1][j]) {
                    dp[i][j] = dp[i][k] + dp[k + 1][j];
                    maxSize = max(maxSize, dp[i][j]);
                }
            }
            
            for (int a = i, b = j; a < b - 1;) {
                int leftSum = dp[i][a];
                int rightSum = dp[b][j];
                if (leftSum && rightSum && leftSum == rightSum && dp[a + 1][b - 1]) {
                    dp[i][j] = leftSum + dp[a + 1][b - 1] + rightSum;
                    maxSize = max(maxSize, dp[i][j]);
                    break;
                } else if (leftSum < rightSum) {
                    a++;
                } else {
                    b--;
                }
            }
        }
    }
    
    cout << maxSize << endl;
    return 0;
}