import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.ArrayDeque;
import java.util.HashMap;
import java.util.Map;

/**
 * Arithmetique
 */
public class Variables {

    public static void main(String[] args) {
        ArrayDeque<Node> pile = new ArrayDeque<>();
        HashMap<String, Integer> ids = new HashMap<>();

        for (String arg : args) {
            try {
                Integer.parseInt(arg);
                pile.addFirst(new Node(arg));
            } catch (NumberFormatException e) {
                if (Character.isUpperCase(arg.charAt(0))) {
                    pile.addFirst(new Node(arg));
                    ids.put(arg, 0);
                } else {
                    if (pile.size() < 2) {
                        System.err.println("Invalid stack size.");
                        return;
                    }
                    Node n2 = pile.pollFirst();
                    Node n1 = pile.pollFirst();

                    Node n3 = new Node(arg);
                    n3.addSubNode(n1);
                    n3.addSubNode(n2);
                    
                    pile.addFirst(n3);
                }
            }
        }

        Node firstNode = pile.pollFirst();
        System.out.println(firstNode.showNode());

        try (BufferedReader br = new BufferedReader(new InputStreamReader(System.in))) {
            for (Map.Entry<String, Integer> entry : ids.entrySet()) {
                System.out.print(entry.getKey() + " ? ");
                ids.put(entry.getKey(), Integer.parseInt(br.readLine()));
            }
        } catch (Exception e) {
            System.out.println(e);
        }

        System.out.println("= " + firstNode.getResult(ids));
    }
}