Simple Calculator

package StacksAndQueues;

import java.util.ArrayDeque;
import java.util.Collections;
import java.util.Scanner;

public class SimpleCalculator {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        String[] action = scanner.nextLine().split("\\s+");
        ArrayDeque<String> numbers = new ArrayDeque<>();
        Collections.addAll(numbers, action);

        while (numbers.size() > 1){
            int first = Integer.parseInt(numbers.pop());
            String operator = numbers.pop();
            int second = Integer.parseInt(numbers.pop());

            switch (operator){
                case "+":
                    numbers.push(String.valueOf(first + second));
                    break;
                case "-":
                    numbers.push(String.valueOf(first-second));
                    break;
            }
        }
        System.out.println(numbers.pop());
    }
}