local mfl, mce = math.floor, math.ceil
local function getprimes(k, x)
  local primes = {}
  local allnums = {}
  for i = 1, x do allnums[i] = true end
  for i = 2, x do
    if allnums[i] then
      if k <= i then
        table.insert(primes, i)
      end
      local lim = mfl(x / i)
      for j = 2, lim do
        allnums[j * i] = false
      end
    end
  end
  return primes
end
local k, n = io.read("*n", "*n")
local primes = getprimes(k, n)
local t = {}
for i = 1, 8 do
  t[i] = 0
end
local maxlen, maxlenpos = 0, 0
local right = #primes
for i = #primes, 1, -1 do
  local p = primes[i]
  local dv = p % 9
  if t[dv] ~= 0 then
    right = math.min(right, t[dv] - 1)
  end
  t[dv] = i
  local len = right - i + 1
  if maxlen < len then
    maxlen = len
    maxlenpos = i
  end
end
print(primes[maxlenpos])