import std.stdio;
import std.conv;
import std.string;
import std.typecons;
import std.algorithm;
import std.array;
import std.range;
import std.math;
import std.regex : regex;
import std.container;
import std.bigint;


void main()
{
  auto x = readln.chomp.split.to!(int[]);
  auto a = new int[](3);
  a[0] = x[0] * x[1];
  a[1] = x[0] + x[1];
  a[2] = x[0] - x[1];
  writeln(max(a[2],max(a[0], a[1])));
}
