n = int(input())
a = [0] + list(map(int, input().split()))
f = [[0] * (n + 1) for _ in range(n + 1)]
for i in range(n, 0, -1):
for j in range(i + 2, n + 1):
f[i][j] = 10**40
for k in range(i + 1, j):
f[i][j] = min(f[i][j], f[i][k] + f[k][j] + a[i] * a[j] * a[k])
print(f[1][n])