#include <stdio.h>
#include <stdlib.h>
int n,k,nr=0;
int cmmdc ( int a, int b ) 
{  
    if (b == 0) return a;  
    return cmmdc(b,a%b);  
}  
void scan()
{
	freopen("frac.in", "r",stdin);
	freopen("frac.out", "w",stdout);
	scanf("%d%d", &n,&k);
}
void solve()
{
	for(int i=1;;++i)
	{
		if(cmmdc(n,i)==1)
			++nr;
		if(nr==k)
		{
			printf("%d\n", i);
			exit(0);
		}
	}
}
int main()
{
	scan();
	solve();
	return 0;
}