#include <iostream>
#include <cstdio>
#include <vector>

using namespace std;

#define DIM 505

unsigned long long d[DIM][DIM];
struct elem {
    int first, second;
} V[DIM];
int N, a, b;

int main() {
    unsigned long long INF = 1000000000000000;
    freopen("podm.in","r",stdin);
    freopen("podm.out","w",stdout);

    scanf("%d\n", &N);
    scanf("%d", &a);

    int b;
    for(int i = 1; i <= N; ++i) {
        scanf("%d", &b);

        V[i].first = a;
        V[i].second = b;
        a = b;
    }

    for(int i = 1; i <= N; ++i) {
        d[i][i] = 0;
    }

    for(int i = 1; i < N; ++i ){
        d[i][i + 1] = 1LL * V[i].first * 1ULL * V[i].second * 1ULL * V[i + 1].second;
    }

    for(int lg = 2; lg < N; ++lg) {
        for(int i = 1; i <= N - lg; ++i) {
            int j = i + lg;

            d[i][j] = INF;
            for(int k = i; k < j; ++k) {
                d[i][j] = min(d[i][j], d[i][k] + d[k + 1][j] + 1ULL * V[i].first * 1ULL * V[k + 1].first * 1ULL * V[j].second);
            }
        }
    }

    cout << d[1][N] << '\n';

    return 0;
}