#include<cstdio>
#include<iostream>
#include<algorithm>
using namespace std;
int n;
long long a[1666666],f[1999999],s[1999999],t,w,sum;
int main(){
	freopen("stick.in","r",stdin);
	freopen("stick.out","w",stdout);
	scanf("%d",&n);
	for(int i=1;i<=n;i++) scanf("%lld",&a[i]),s[a[i]]++;//记录多少个
	sort(a+1,a+n+1);
	for(int i=n;i>=1;i--)
		if(s[a[i]]%2==1){
			if(s[a[i]]==1&&f[a[i]]==1) break;
			s[a[i]]--,s[a[i]-1]++,a[i]--,f[a[i]]=1;}//削奇数个
	sort(a+1,a+n+1);w=1;
	for(int i=n;i>=1;i--){
		if(s[a[i]]>=8)
			sum+=(s[a[i]]/4-1)*a[i]*a[i],s[a[i]]=s[a[i]]%4+4;//四个的组成正方形
		while(s[a[i]]>=2){
			t++;
			if(t%2==0)	sum+=a[i]*a[w];
			else w=i;
			s[a[i]]-=2;} }	//长方形
	printf("%lld",sum);
}

#include<cstdio>
#include<iostream>
using namespace std;
int n, a[366666],f[399999],p[399999],tot=0,max1=-8;
int main(){
	freopen("select.in","r",stdin);
	freopen("select.out","w",stdout);
	scanf("%d",&n);
	for(int i=1;i<=n;i++)
		scanf("%d",&a[i]);	
	for(int i=1;i<=n;i++) 
	{
		int l=i-1,r=i+1;
		while(a[l]%a[i]==0&&a[l]>=a[i])l--;
		while(a[r]%a[i]==0&&a[r]>=a[i])r++;
		r--,l++;
		max1=max(max1,r-l+1);
	}
	for(int i=1;i<=n;i++)
	{
		int l=i-1,r=i+1;
		while(a[l]%a[i]==0&&a[l]>=a[i])l--;
		while(a[r]%a[i]==0&&a[r]>=a[i])r++;
		r--,l++;
		if(r-l+1==max1&&!f[l]) tot++,p[tot]=l,f[l]=1;
	}
	printf("%d %d\n",tot,max1);
	for(int i=1;i<=tot;i++)
	printf("%d ",p[i]);
}

#include<cstdio>
#include<map>
using namespace std;
int f[1999999]; int tot;int p,l,r;
void dfs(int x,int a,int b)
{
	if(x>p||a*b>r||b+1>r)return ;//少了这句话就30
	dfs(x+1,a,b+1);
	if(!f[a*b])
	{
		f[a*b]=1;
		
	}
	if(b!=0)
	dfs(x+1,a*b,b);
}
int main(){
	freopen("number.in","r",stdin);
	freopen("number.out","w",stdout);
	scanf("%d%d%d",&l,&r,&p);
	f[1]=1;
	dfs(1,1,0);
	for(int i=l;i<=r;i++)
	{
		if(f[i])
		tot++;
	}
	printf("%d",tot);	
}