var main = function(input) {
  input = input.split(' ').map(x=>parseInt(x));
  var a = input[0];
  var b = input[1];
  var max　= a+b;
  if(max<a-b){
    max = a-b;
  }
  if(max<a*b){
    max=a*b;
  }
  if(max === -0){
    max = 0;
  }
  console.log(max);

    return 0; 
}

main(require("fs").readFileSync("/dev/stdin", "utf8"));
