function Main(s){
	s=s.split(/\s/);
	s.forEach(function(e,i,a){a[i]=Number(a[i]);});
	var a=s[0]+s[1];
	var b=s[0]-s[1];
	var c=s[0]*s[1];
	a=a>b?a:b;
	a=a>c?a:c;
}
Main(require("fs").readFileSync("/dev/stdin", "utf8"));