const main = function(input){
  var nums = input.split(" ").map(i => parseInt(i));
  var add = nums[0]+nums[1];
  var sub = nums[0]-nums[1];
  var mul = nums[0]-nums[1];
  
  var ans = add;
  ans = Math.max(ans,sub);
  ans = Math.max(ans,mul);
  
  console.log(ans);
  
}


main(require('fs').readFileSync('/dev/stdin', 'UTF-8'));