Problem:
Score : 100 points

Problem Statement

There are N slimes lining up in a row.
Initially, the i-th slime from the left has a size of a_i.

Taro is trying to combine all the slimes into a larger slime.
He will perform the following operation repeatedly until there is only one slime:

Choose two adjacent slimes, and combine them into a new slime. The new slime has a size of x + y, where x and y are the sizes of the slimes before combining them. Here, a cost of x + y is incurred. The positional relationship of the slimes does not change while combining slimes.

Find the minimum possible total cost incurred.

Constraints

All values in input are integers.

2 \leq N \leq 400

1 \leq a_i \leq 10^9

Input

Input is given from Standard Input in the following format:

N
a_1 a_2 \ldots a_N

Output

Print the minimum possible total cost incurred.

Sample Input 1

4
10 20 30 40

Sample Output 1

190

Taro should do as follows (slimes being combined are shown in bold):

(10, 20, 30, 40) → (30, 30, 40)

(30, 30, 40) → (60, 40)

(60, 40) → (100)

Sample Input 2

5
10 10 10 10 10

Sample Output 2

120

Taro should do, for example, as follows:

(10, 10, 10, 10, 10) → (20, 10, 10, 10)

(20, 10, 10, 10) → (20, 20, 10)

(20, 20, 10) → (20, 30)

(20, 30) → (50)

Sample Input 3

3
1000000000 1000000000 1000000000

Sample Output 3

5000000000

The answer may not fit into a 32-bit integer type.

Sample Input 4

6
7 6 8 6 1 1

Sample Output 4

68

Taro should do, for example, as follows:

(7, 6, 8, 6, 1, 1) → (7, 6, 8, 6, 2)

(7, 6, 8, 6, 2) → (7, 6, 8, 8)

(7, 6, 8, 8) → (13, 8, 8)

(13, 8, 8) → (13, 16)

(13, 16) → (29)

Solution in C++14 (GCC 5.4.1) (judge verdict: Accepted)

#include<iostream>
#include<iomanip>
#include<vector>
#include<string>
#include<cstring>
#include<map>
#include<set>
#include<queue>
#include<stack>
#include<algorithm>
#include<cmath>
#include<cstdio>
#include<cstdlib>
#include<climits>
#include<fstream>

#define MOD (1000000007)

using namespace std;

typedef long long int Int;

int N;
Int A[500];
Int sum[500];
Int dp[500][500];

int main(void) {
    cin>>N;

    for(int i = 0;i < N;i++) {
        cin>>A[i];
        if(i > 0)
            sum[i] = sum[i-1]+A[i];
        else
            sum[i] = A[i];
        dp[i][i] = A[i];
    }

    for(int len = 2;len <= N;len++) {
        for(int l = 0;l+len <= N;l++) {
            int r = l+len-1;
            dp[l][r] = 1LL<<61;
            for(int k = l;k <= r;k++) {
                dp[l][r] = min(dp[l][r],dp[l][k]+dp[k+1][r]+sum[r]-sum[l-1]);
            }
        }
    }

    cout<<dp[0][N-1]-sum[N-1]<<endl;

    return 0;
}