function main(input){
  const a = input.trim().split(' ');
  const n = parseInt(a[0], 10),
        m = parseInt(a[1], 10);
  let ans = Math.max(n+m, n-m, n*m);
  if(ans==0){
    console.log(0);
  }else{
    console.log(ans);
  }
}
main(require('fs').readFileSync('/dev/stdin', 'utf8'));