#include <iostream>
#include <fstream>
#include <cmath>
#include <algorithm>

#define ll unsigned long long 
#define MAX 1000001


using namespace std;

ifstream in("frac.in");
ofstream out("frac.out");

ll n, p, a[MAX], d = 2, nr = 0, r;

int main() {
	in >> n >> p;
	while (n != 1) {
		if (n % d == 0) {
			for (ll i = d; i < MAX; i += d) a[i] = 1;
			while (n % d == 0) n /= d;
		}
		d++;
	}

	for (int i = 1; i < 30 && nr != p; i++) {
		if (a[i] == 0) nr++, r = i;	  
	}
	out << r;
}