#include<stdio.h>
#include<assert.h>

#include<algorithm>
#include<vector>

using namespace std;

struct mat{
  long long h, w;

  mat(){};
};

const int knmax = 505;
long long matrixes, sol, dp[knmax][knmax];
mat given[knmax];

void read(){
  assert(freopen("podm.in", "r", stdin));

  scanf("%lld", &matrixes);

  for(int i = 1; i <= matrixes; ++i)
    scanf("%lld", &given[i].h);

  scanf("%lld", &given[matrixes].w);

  for(int i = 1; i < matrixes; ++i)
    given[i].w = given[i + 1].h;
}

long long compute(int x, int y){
  if(x == y)
    return 0;

  if(dp[x][y])
    return dp[x][y];

  dp[x][y] = given[x].h * given[x].w * given[y].w + compute(x + 1, y);

  for(int i = x + 1; i <= y; ++i)
    dp[x][y] = min(dp[x][y], compute(x, i - 1) + compute(i, y) + given[x].h * given[i].h * given[y].w);

  return dp[x][y];
}

void solve(){
  sol = compute(1, matrixes);
}

void write(){
  assert(freopen("podm.out", "w", stdout));

  printf("%lld", sol);
}

int main(){
  read();
  solve();
  write();
  return 0;
}