#include<bits/stdc++.h>
using namespace std;
long long m,n,a[100005],b[100005],ans[100005];
int main()
{
	freopen ("humble.in","r",stdin);
	freopen ("humble.out","w",stdout);
    scanf("%d%d",&m,&n);
    for (int i=1;i<=m;i++)
    {
        scanf("%d",&a[i]);
        b[i]=1;
    }
    ans[1]=1;
    for (int i=2;i<=n+1;i++)
    {
        ans[i]=10000000000;
        for (int j=1;j<=m;j++)
        {
            while (a[j]*ans[b[j]]<=ans[i-1]) 
			b[j]++;
            if (a[j]*ans[b[j]]<ans[i]) 
			ans[i]=a[j]*ans[b[j]];
        }
    }
    printf("%d",ans[n+1]);
    return 0;
}