import dibo.*;

public class Aufgabe28 {

  public static char lookahead;

  public static void nextToken() {
    lookahead = Terminal.readChar();
  } 

  public static void match(char token) {
    if (lookahead == token) {
      nextToken();
    } else {
      System.out.println("Fehler: ungueltiges Token!");
    }
  }

  public static int expression() {
    int value1 = term(); 
    if (lookahead == '+') {
      match('+'); 
      int value2 = term();
      return value1 + value2;
    } else {
      return value1;
    }
  }

  public static int term() {
    int value1 = factor(); 
    if (lookahead == '*') {
      match('*'); 
      int value2 = factor();
      return value1 * value2;
    } else {
      return value1;
    }
  }

  public static int factor() {
    if (isDigit(lookahead)) {
      int value = getValue(lookahead);
      match(lookahead);
      return value;
    } else if (lookahead == '(') {
      match('('); 
      int value = expression(); 
      match(')');
      return value;
    } else {
      System.out.println("Fehler: ungueltiges Token!");
      return 0;
    }
  }

  public static void main(String[] args) {
    try {

      nextToken();
      int result = expression();
      System.out.println("Result: " + result);

    } catch (Exception e) {
      System.out.println(e);
    }
  }

  // Hilfsfunktionen

  public static boolean isDigit(char zeichen) {
    return (zeichen >= '0') && (zeichen <= '9');
  }

  public static int getValue(char zeichen) {
    return (int)(zeichen-'0');
  }

}