N,K=map(int,input().split())

x=N
import math 
L=int(math.sqrt(x))

FACT=dict()

for i in range(2,L+2):
    while x%i==0:
        FACT[i]=FACT.get(i,0)+1
        x=x//i

if x!=1:
    FACT[x]=FACT.get(x,0)+1

ANS=[]
for i in range(1,N):

    #素因数の個数
    j=i
    COMPRIME=0
    
    for f in FACT:
        com=FACT[f]

        com_f=0
        while j%f==0 and com_f<com:
            j//=f
            com_f+=1

        COMPRIME+=com_f

    #print(j,COMPRIME)

    if COMPRIME<K:
        continue
    ANS.append(i)


ANS2=[]
for ans in ANS:
    x=ans

    L=int(math.sqrt(x))
    FACT=dict()
    
    for i in range(2,L+2):
        while x%i==0:
            FACT[i]=FACT.get(i,0)+1
            x=x//i

    if x!=1:
        FACT[x]=FACT.get(x,0)+1

    ANSNUM=1
    for f in FACT.values():
        ANSNUM*=f+1

    ANS2.append(ANSNUM)

print(ANS[ANS2.index(max(ANS2))])