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