# ---------------------
# standard answer (TLE)

require 'prime'

l,h=gets.split(" ").map(&:to_i)

m=nil;t=nil
h.downto(l){|n|
    t=Prime.prime_division(n)[0][0]
    m=[t,n] if t!=n&&(!m||m[0]<t)
}
p m[1]