#include <stdio.h>
#include <bitset>

using namespace std;

#define MAXNR 1500005
bitset<MAXNR> ver;
int m, n, prim;

int main()
{
	int i,j;
	FILE *in = fopen("numar2.in", "r");
	FILE *out= fopen("numar2.out","w");
	fscanf(in, "%i %i", &n, &m);
	for(i = 1; i <= n; i++)
	{
		fscanf(in, "%i", &prim);
		for(j = 1; prim * j < MAXNR; j++)
			ver[prim * j] = 1;
	}
	int nr = 0;
	for(i = 1; i <= MAXNR; i++)
	{
		if(nr == m)
		{
			fprintf(out,"%i", i - 1);
			return 0;
		}
		if(ver[i] == 1)
			nr++;
	}
}