require 'prime'
L, H = gets.split.map(&:to_i)
i = 2
factor = 0
ans = 0
while i * i <= H
    (H / i).downto(i){|j|
        if i * j < L
            break
        end
        tmp = Prime.prime_division(i * j)[0][0]
        if factor < tmp
            factor = tmp
            ans = i * j
        end
        if factor > i
            p ans
            exit
        end
        }
    i += 1
end
p ans