#include <cstdio>
#define dim 503
int n,i,j,k;
long d[dim],c[dim][dim];
int main() {
	freopen("podm.in","r",stdin);
	freopen("podm.out","w",stdout);
	scanf("%d",&n);
	for(i=1;i<=n;i++)
		scanf("%ld",&d[i]);
	for(i=2;i<=n;i++)
		for(j=i;j<=n;j++)
		{
			if(i==j) c[i][j]=0;
			else
			{
				for(k=i;k<=j;k++)					
					c[i][j]=c[i][i+k-1]+c[i+k][j]+(d[i-1]*d[i]*d[j]);
			}
		}
			
	printf("%ld",c[1][n]);
	return 0;
}