#include<stdio.h>
int k=0;
int v[12000000]={0};
void phi(int n){
	int i, j;
	for(i=2; i<=n;++i)
		if(v[i]==0)
		if(n%i==0)
		for(j=i; j<=n;j=j+i)
		if(v[j]==0)
		{
			k++;
			v[j]=1;
		}
}
int caut(int n, int p){
	phi(n);
	int nr=0, i, j;
	v[1]=0;
	for(i=1; nr<p;++i)
		if(v[i]==0){
			nr++;
			j=i;
		}
	return j;
}
		
	
	

int main(){
	freopen("frac.in", "r", stdin);
	freopen("frac.out", "w", stdout);
	int n, p;
	scanf("%d", &n);
	scanf("%d", &p);
	printf("%d", caut(n, p));
	
	
	
	
	
	
	
	
	
	
	
	
	
	
	
	return 0;}