var Queue = function (){
    this.oldStack = new Stack ();
    this.newStack = new Stack ();
  }

Queue.prototype.add = function (value){
  this.newStack.push(value);
}

Queue.prototype.size = function (){
  return this.oldStack.size + this.newStack.size;
}

Queue.prototype.sync = function (){

  if (this.oldStack.isEmpty()){

    while(!this.newStack.isEmpty()){

      this.oldStack.push(this.newStack.pop());
    }
  }
}

Queue.prototype.peek = function (){
  this.sync();
  return this.oldStack.peek();
}

Queue.prototype.remove = function (){
  this.sync();
  return this.oldStack.pop();
}