rt,不开O2 100pts,开了只剩60pts

#include<bits/stdc++.h>
using namespace std;
#define ull unsigned long long
#define ll  long long
long long read(){
	long long x=0,sgn=1;char ch=getchar();
	while(ch<'0' || ch>'9'){if(ch=='-')sgn=-1;ch=getchar();}
	while(ch>='0' && ch<='9'){x=(x<<3)+(x<<1)+(ch&15);ch=getchar();}
	return x*sgn;
}
ll n,m,ans,cnt;
ll a[100010];
ll b[100010];
int main() {
	cin>>n>>m;
	for(int i=1;i<=n;i++) cin>>a[i];
    sort(a+1,a+n+1);
	for(int i=1;i<=a[n];i++){
		cnt=0;
		for(int k=1;k<=n;k++){
            b[k]=a[k];
			cnt=cnt+b[k]/i;
			b[k]=b[k]%i;
		}
		if(cnt>=m/2){
			sort(b+1,b+n+1);
			ll tmp=0;
			ll l=n;
			if(cnt<m){
				cnt=cnt-m/2;
				tmp=tmp+cnt*i;
				for(int j=cnt;j<m/2;j++)
					tmp=tmp+b[l--];
			}
			else tmp=m*i/2;
			ans=max(ans,tmp);
		}			
	}
	cout<<ans<<endl;
    return 0;
}