#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp> 
#include <ext/pb_ds/tree_policy.hpp> 
using namespace std;
using namespace __gnu_pbds;

#define ordered_set tree<int, null_type,less_equal<int>, rb_tree_tag,tree_order_statistics_node_update>
#define pb push_back
#define ff first
#define ss second
#define endl '\n'
#define fast ios::sync_with_stdio(false); cin.tie(NULL);
const double eps = 1e-6;

/////////////////////////////////////////////

void __print(int x) {cerr << x;}
void __print(long x) {cerr << x;}
void __print(long long x) {cerr << x;}
void __print(unsigned x) {cerr << x;}
void __print(unsigned long x) {cerr << x;}
void __print(unsigned long long x) {cerr << x;}
void __print(float x) {cerr << x;}
void __print(double x) {cerr << x;}
void __print(long double x) {cerr << x;}
void __print(char x) {cerr << '\'' << x << '\'';}
void __print(const char *x) {cerr << '\"' << x << '\"';}
void __print(const string &x) {cerr << '\"' << x << '\"';}
void __print(bool x) {cerr << (x ? "true" : "false");}

template<typename T, typename V>
void __print(const pair<T, V> &x) {cerr << '{'; __print(x.first); cerr << ','; __print(x.second); cerr << '}';}
template<typename T>
void __print(const T &x) {int f = 0; cerr << '{'; for (auto &i: x) cerr << (f++ ? "," : ""), __print(i); cerr << "}";}
void _print() {cerr << "]\n";}
template <typename T, typename... V>
void _print(T t, V... v) {__print(t); if (sizeof...(v)) cerr << ", "; _print(v...);}
#ifndef ONLINE_JUDGE
#define debug(x...) cerr << "[" << #x << "] = ["; _print(x)
#else
#define debug(x...)
#endif

////////////////////////////////

#define int long long
int k;
int solvepos(int a[],int n){

	vector<int> pos , neg;
	//debug("Pos call hua");
	for(int i = 0 ;i < n ; ++i){

		if(a[i] > 0)
			pos.pb(a[i]);
		else if(a[i] < 0)
			neg.pb(a[i]);
	}

	sort(pos.begin(),pos.end());
	sort(neg.begin(),neg.end());
	reverse(pos.begin(),pos.end());
	//reverse(neg.begin(),neg.end());
	//debug(pos , neg);
	int l = 1 , r = 1e18;
	int ans = 0;
	int ps = pos.size();
	int ns = neg.size();
	while(l <= r){

		int mid = l + (r-l)/2;

		int j = ps-1;
		int tot = 0;
		for(int i = 0 ; i < ps ; ++i){

			while(j > i && pos[i]*pos[j] <= mid)
				--j;
			tot += min((ps-i-1) , (ps-j-1));
		}
		j = (int)neg.size() - 1;
		int x = 0;
		for(int i = 0 ; i < ns ; ++i){

			while(j > i && neg[i]*neg[j] <= mid)
				--j;
			x += min((ns-i-1) , (ns-j-1));
		}
		//debug(x , tot);
		tot += x;
		if(tot < k){

			//debug(tot , k);
			l = mid + 1;
		}
		else {

			ans = mid;
			r = mid - 1;
		}
	}

	return ans;
}

int solveneg(int a[] , int n){

	//debug("Neg call hua");
	vector<int> pos , neg;
	for(int i = 0 ;i < n ; ++i)
		if(a[i] < 0)
			neg.pb(a[i]);
		else if(a[i]> 0)
			pos.pb(a[i]);

	sort(pos.begin(),pos.end());
	sort(neg.begin(),neg.end());

	reverse(pos.begin(),pos.end());
	reverse(neg.begin(),neg.end());
	//debug(pos,neg);
	int l = -1e18;
	int r = -1;
	int ans;
	while(l <= r){

		int mid = l + (r-l)/2;

		int tot = 0;
		int j = 0;

		for(int i = 0 ; i < neg.size() ; ++i){

			while(j < pos.size() && pos[j]*neg[i] <= mid){

				++j;
			}

			tot+=j;
		}

		if(tot < k){

			l = mid + 1;
		}
		else {

			ans = mid;
			r = mid-1;
		}
	}

	return ans;
}

void solve(){

	int n;
	cin>>n>>k;
	int a[n];
	for(int i = 0 ; i < n ; ++i)
		cin>>a[i];

	int pos = 0 , neg = 0 , zero = 0;

	for(int i = 0 ; i < n ; ++i){

		if(a[i]> 0 )
			++pos;
		else if(a[i]==0 )
			++zero;
		else if(a[i] < 0)
			++neg;
	}

	int totneg = pos*neg;
	int totzero = zero*(2*(n-1) - (zero-1))/2;
	int ans = 0;
	if(k <= totneg)
		ans = solveneg(a , n);
	else if(k <= totneg + totzero)
		ans = 0;
	else{
		k = k - (totneg + totzero);
		//debug(k , totneg , totzero);
		ans = solvepos(a , n);
	}

	cout<<ans<<endl;
}


signed main(){

    fast;
    int t = 1;
    //cin>>t;
    for(int i = 1 ; i <= t; ++i){

    	solve();
    }
}


Measured memory_bytes: 3956