public void sort(){
		java.util.Stack<Integer> spare_stack=new java.util.Stack<Integer>();
		while(!this.stack.empty()){
			int current=this.stack.pop();
			while(!spare_stack.empty() && spare_stack.peek()>current){
				this.stack.push(spare_stack.pop());
			}
			spare_stack.push(current);
		}
		while(!spare_stack.empty()){
			this.stack.push(spare_stack.pop());
		}
	}