题目到是不难，主要是用了set，方便。
/*
ID: rowanha3
LANG: C++
TASK: humble
*/
#include<bits/stdc++.h>
using namespace std;
#define LL long long
set<LL>se;
set<LL>::iterator it;
LL num[111];
int main()
{freopen("humble.in","r",stdin);freopen("humble.out","w",stdout);int n,m,i,j,a,b;while(~scanf("%d%d",&n,&m)){se.clear();for(i=1;i<=n;i++){cin>>num[i];se.insert(num[i]);}for(i=1;i<=n;i++){it=se.begin();while(1){LL p=(*it)*num[i];if(p<0)break;if(se.size()>m){se.erase(--se.end());if(p>(*(--se.end())))break;}se.insert(p);it++;}}cout<<*(--se.end())<<endl;}return 0;
}