def p(q):
 if q&1==0:return False
 return pow(2,q-1,q)==1
a=[0,0,0,0,3,0,5,0,7,7,7,0,11,0,13,7,7,0,8,0,19,19,7,0,23,23]
x=input()
if x<26:print a[x]
elif (x-1)%8==0 and p(x-8):print 14
else:print 8