Cypher Roulette

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class CypherRoulette {

    public static void main(String[] args) throws IOException {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));

        int numberOfLines = Integer.parseInt(reader.readLine());

        StringBuilder cypherString = new StringBuilder();

        String lastChars = null;

        boolean appendDirection = false;

        for (int i = 0; i < numberOfLines; i++) {
            String currentLine = reader.readLine();

            if (currentLine.equals("spin")) {
                // toggle direction
                appendDirection = !appendDirection;

                // increment because "spin" commands do not count towards the N count
                numberOfLines++;
            } else {
                if (appendDirection) {
                    // insert currentLine at the beginning of cypherString
                    cypherString.insert(0, currentLine);
                } else {
                    // append at the end of cypherString
                    cypherString.append(currentLine);
                }
            }

            if (currentLine.equals(lastChars)) {
                cypherString.delete(0, cypherString.length());
            }

            lastChars = currentLine;
        }

        System.out.println(cypherString.toString());
    }
}