diff --git a/src/flashcards/Main.java b/src/flashcards/Main.java
index d1b036c..f21f823 100644
--- a/src/flashcards/Main.java
+++ b/src/flashcards/Main.java
@@ -1,7 +1,177 @@
 package flashcards;
 
 public class Main {
-    public static void main(String[] args) {
-        System.out.print("Hello world!");
-    }
-}
\ No newline at end of file
+	private static Map<String, String> cards = new LinkedHashMap<>();
+	private static Scanner scanner = new Scanner(System.in);
+	private static ArrayList<String> cardsInArray = new ArrayList();
+	private static List<String> logs = new ArrayList<>();
+	
+	public static void main(String[] args) {
+	     
+		String action;
+	    
+		while (true) {
+			System.out.println(cards);
+			System.out.print("Input the action (add, remove, import, export, ask, exit): ");
+			action = scanner.next();
+			
+			switch (action){
+				case "add":
+					add();
+					break;
+				case "remove":
+					remove();
+					break;
+				case "import":
+					imp();
+					break;
+				case "export":
+					exp();
+					break;
+				case "ask":
+					ask();
+					break;
+				case "log":
+					log();
+					break;
+				case "hardest card":
+					hardestCard();
+					break;		
+				case "exit":
+					System.out.println("Bye bye!");
+					System.exit(0);
+					break;
+				default :
+					System.out.println("Unknown operation. Repeat action: ");
+			}
+		}
+	}
+	
+	private static void add() {
+		String card;
+		String definition;
+		System.out.print("The card: ");
+		
+		while (true) {
+			card = scanner.next();
+			if (cards.containsKey(card)) {
+				System.out.print("Such card is exist. Input another card: ");
+			}
+			else {
+				System.out.print("The definition of the card: ");
+				definition = scanner.next();
+				cards.put(card, definition);
+				cardsInArray.add(card);
+				break;
+			}
+		}	
+		System.out.println("The pair (\""+ card +"\":\""+ definition +"\") is added.");
+	}
+	
+	private static void remove() {
+		String card;
+		System.out.print("The card: ");
+		card = scanner.next();
+		if (cards.containsKey(card)) {
+			cards.remove(card);
+			cardsInArray.remove(card);
+		}
+		else {
+			System.out.println("Can't remove \""+ card +"\": there is no such card.");
+		}	
+	}
+	
+	private static void exp() {
+		System.out.println("Enter filename: ");
+		String filename = scanner.next();
+		File file = new File(filename);
+		int count = 0;
+		try {
+			BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter(file));
+			if (!file.exists()) {
+				file.createNewFile();
+			}
+			
+			for (Map.Entry<String, String> card : cards.entrySet()) {
+				bufferedWriter.write(card.getKey());
+				bufferedWriter.append("\n");
+				bufferedWriter.write(card.getValue());
+				bufferedWriter.append("\n");
+				count++;
+			}
+			bufferedWriter.flush();
+			bufferedWriter.close();
+		} catch (IOException e) {
+			e.printStackTrace();
+		}	
+		System.out.println(count +" cards have been loaded.");
+	}
+	
+	private static void imp() {
+		System.out.println("Enter filename: ");
+		String filename = scanner.next();
+		File file = new File(filename);
+		int count = 0;
+		
+		try {
+			BufferedReader  bufferedReader  = new BufferedReader(new FileReader(file));
+			while (bufferedReader.ready()) {
+				cards.put(bufferedReader.readLine(), bufferedReader.readLine());
+			}
+			bufferedReader.close();
+		} catch (IOException e) {
+			e.printStackTrace();
+		}	
+	}
+	
+	private static void ask() {
+		int askNumber;
+		String answer;
+		Random random = new Random();
+		int randomNumber;
+		
+		System.out.println("How many times to ask?");
+		askNumber = scanner.nextInt();
+		
+		for (int i = 0; i < askNumber; i++ ) {
+			randomNumber = random.nextInt(cardsInArray.size());
+			System.out.println("Print the definition of \""+ cards.get(cardsInArray.get(randomNumber))+"\":");
+			answer = scanner.next();
+			if (answer.equals(cards.get(cardsInArray.get(randomNumber)))) {
+				System.out.println("Correct answer.");
+			}
+			else if (cards.containsValue(answer)) {
+				System.out.println("Wrong answer. You've just written a definition of another card.");
+			}
+			else {
+				System.out.println("Wrong answer.");
+			}
+		}
+	}
+	
+	
+	private static void checkCards() {
+		String answer;
+		for (Map.Entry<String, String> card : cards.entrySet()) {
+			System.out.println("Print the definition of \""+ card.getKey()+"\":");
+			answer = scanner.next();
+			if (answer.equals(card.getValue())) {
+				System.out.println("Correct answer.");
+			}
+			else if (cards.containsValue(answer)) {
+				System.out.println("Wrong answer (The correct one is \""+ card.getValue() +"\"). You've just written a definition of another card.");
+			}
+			else {
+				System.out.println("Wrong answer (The correct one is \""+ card.getValue() +"\").");
+			}
+		}
+	}
+	
+	private static void log() {
+		 
+	}
+	
+	private static void hardestCard() {
+		
+	}    
+}