require 'prime'
L, H = gets.split.map(&:to_i)
factor = 0
ans_list = []
(Math.sqrt(H).round).downto(2){|i|
    flag = false
    (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_list.clear
            
        end
        if factor == tmp
            ans_list.push(i * j)
        end
        if factor > i
            flag = true
            break
        end
        }
    break if flag
    }
p ans_list.max