import scala.collection.immutable.IndexedSeq

object Main {
  def sieve(n: Int): IndexedSeq[Int] = {
    val isNotPrime = scala.collection.mutable.BitSet(n + 1)
    for (i <- 2 to n) if (!isNotPrime(i))
      for (j <- (i + i) to n by i) isNotPrime(j) = true
    return (2 to n).filter(!isNotPrime(_))
  }

  def main(args: Array[String]): Unit = {
    val Array(l, h) = readLine.split(' ').map(_.toLong)
    val primes = sieve(110000).reverse
    for (p <- primes.map(_.toLong)) {
      if (l <= p * p && p * p <= h) {
        for (q <- primes) if (l <= p * q && p * q <= h) {
          println(p * q)
          return
        }
      }
    }
    val factorList = new Array[Int]((h - l).toInt + 1)
    for (p <- primes)
      for (i <- (Array(l - l % p, p + p).max - l).toInt to (h - l).toInt by p)
        if(0 <= i) factorList(i) = p
    println(factorList.zipWithIndex.max._2 + l)
  }
}