import std.conv, std.stdio, std.string;
import std.algorithm, std.array, std.bigint, std.container, std.math, std.numeric, std.range, std.regex, std.typecons;
import core.bitop;

class EOFException : Throwable { this() { super("EOF"); } }
string[] tokens;
string readToken() { for (; tokens.empty; ) { if (stdin.eof) { throw new EOFException; } tokens = readln.split; } auto token = tokens.front; tokens.popFront; return token; }
int readInt() { return readToken.to!int; }
long readLong() { return readToken.to!long; }
real readReal() { return readToken.to!real; }

bool chmin(T)(ref T t, in T f) { if (t > f) { t = f; return true; } else { return false; } }
bool chmax(T)(ref T t, in T f) { if (t < f) { t = f; return true; } else { return false; } }

int binarySearch(T)(in T[] as, in bool delegate(T) test) { int low = -1, upp = cast(int)(as.length); for (; low + 1 < upp; ) { int mid = (low + upp) >> 1; (test(as[mid]) ? low : upp) = mid; } return upp; }
int lowerBound(T)(in T[] as, in T val) { return as.binarySearch((T a) => (a < val)); }
int upperBound(T)(in T[] as, in T val) { return as.binarySearch((T a) => (a <= val)); }


enum LIM = 10^^5;

bool[] isnp;
long[] primes;

void prepare() {
  isnp = new bool[LIM];
  foreach (i; 2 .. LIM) {
    if (!isnp[i]) {
      primes ~= i;
      for (int j = 2 * i; j < LIM; j += i) {
        isnp[j] = true;
      }
    }
  }
}

void main() {
  prepare();
  
  try {
    for (; ; ) {
      const L = readLong();
      const H = readLong();
      long ans;
      foreach_reverse (i, p; primes) {
        for (long n = H / p * p; n >= L && n >= p^^2; n -= p) {
          bool ok = true;
          foreach (j, q; primes[0 .. i]) {
            if (n % q == 0) {
              ok = false;
              break;
            }
          }
          if (ok) {
            ans = n;
            goto found;
          }
        }
      }
     found:
      writeln(ans);
    }
  } catch (EOFException e) {
  }
}