#include <bits/stdc++.h>
using namespace std;
typedef long long LL;
LL s[110], a[1110000];
int p[110];
int main()
{
    int n, k; scanf("%d%d", &n, &k);
    for(int i=1; i<=n; i++) scanf("%lld", &s[i]);
    memset(p, 0, sizeof(p));
    a[0] = 1;
    for(int i=1; i<=k; i++)
    {
        LL minx = (LL)1 << 32;
        for(int j=1; j<=n; j++)
        {
            if(minx > s[j] * a[p[j]]) minx = s[j] * a[p[j]];
        }
        a[i] = minx;
        for(int j=1; j<=n; j++)
        {
            while(a[i] >= s[j] * a[p[j]]) p[j]++;
        }
    }
    printf("%lld\n", a[k]);
    return 0;
}