import java.util.Arrays;
import java.util.List;
import java.util.Stack;

public class Test {

    public static void main(String[] args) {
        Stack<String> stack = new Stack<>();
        int result = 0;
        String inputString = "5 7 + 3 - 5 +";
        List<String> operators = Arrays.asList("+", "-");
        String[] params = inputString.split(" ");
        for (String op: params) {
            if (operators.contains(op)) {
                if (stack.size() == 2) {
                    result += Integer.parseInt(stack.pop());
                }

                int second = Integer.parseInt(stack.pop());

                if (op.equals("+")) {
                    result += second;
                }
                else if(op.equals("-")) {
                    result -= second;
                }
            }
            else {
                stack.push(op);
            }
        }

        System.out.println("Result: " + result);
    }
}