diff --git a/src/main/java/leets/land/UpdownApplication.java b/src/main/java/leets/land/UpdownApplication.java
index 09d7ae5..89dde2d 100644
--- a/src/main/java/leets/land/UpdownApplication.java
+++ b/src/main/java/leets/land/UpdownApplication.java
@@ -1,8 +1,160 @@
 package leets.land;
+import java.util.InputMismatchException;
+import java.util.Random;
+
+import java.util.Scanner;
 
 public class UpdownApplication {
+	public int get_random_number(){
+		Random r = new Random();
+
+		return r.nextInt(100)+1;
+	}
+	public char get_random_alphabet(){
+		Random r = new Random();
+		int randomChar = r.nextInt(52); // 0부터 51까지의 난수 생성
+		if (randomChar < 26) {
+			// 대문자 선택
+			return (char)('A' + randomChar);
+		} else {
+			// 소문자 선택
+			return (char)('a' + randomChar - 26);
+		}
+	}
+
+	public int select_version() throws Exception {
+		Scanner sc = new Scanner(System.in);
+		int version = 0;
+		boolean valid = false;
+		while (!valid) {
+			try {
+				System.out.println("버전을 선택하세요 (1 또는 2): ");
+				String input = sc.nextLine();
+				version = Integer.parseInt(input);
+				if(version != 1 && version != 2) {
+					throw new Exception(); // 1과 2 아닌 숫자여도 예외
+				}
+				valid = true; // 1또는 2 입력
+			}
+			catch (NumberFormatException e) {
+				System.out.println("[ERROR] 입력 문자의 타입이 맞지 않습니다.");
+			}
+			catch (Exception e) {
+				System.out.println("[ERROR] 존재하지 않는 버전입니다.");
+			}
+
+		}
+
+		if(version==1){
+			return 1;
+		}
+		else if (version==2){
+			return 2;
+		}
+		return 0;
+
+	}
+
+	void checkNumberValidity(int min, int max, int userInput) throws Exception {
+		if(userInput<min || userInput>max){
+			throw new Exception("[ERROR] 범위 내의 숫자를 입력하세요.");
+		}
+	}
+	void run() throws Exception {
+		System.out.println("버전을 입력해주세요 (숫자 버전: 1, 영어 버전: 2) : ");
+		Scanner sc = new Scanner(System.in);
+		int version = select_version();
+		int tryNum = 0;
+		if(version == 1){
+			int answer = get_random_number();
+			int userNumber = -1;
+			int min = 1;
+			int max = 100;
+			while(answer != userNumber){
+				System.out.println("숫자를 입력해주세요 (" +min +" ~ "+max + ") : ");
+				try{
+					String input = sc.nextLine();
+					userNumber = Integer.parseInt(input);
+				}
+				catch (NumberFormatException  e){
+					System.out.println("[ERROR] 입력 문자의 타입이 맞지 않습니다.");
+					continue;
+				}
+				try {
+					checkNumberValidity(min, max, userNumber);
+
+				}
+				catch(Exception e){
+					System.out.println(e.getMessage());
+					continue;
+				}
+				if (answer > userNumber) {
+					System.out.println("UP");
+					min = userNumber + 1;
+				} else if (answer < userNumber) {
+					System.out.println("DOWN");
+					max = userNumber - 1;
+				} else {
+					System.out.println("정답!");
+				}
+				tryNum++;
+
+			}
+
+		}
+		else if(version == 2){
+			char answer = get_random_alphabet();
+			char userAlphabet = ' ';
+			char min = 'A';
+			char max = 'z';
+			while(answer != userAlphabet){
+				System.out.println("영어를 입력해주세요 (" +min +" ~ "+max + ") : ");
+				try{
+					userAlphabet = sc.nextLine().charAt(0);
+					if(!Character.isLetter(userAlphabet)) {
+						throw new InputMismatchException(); // 문자가 아닌 경우 예외 발생
+					}
+				}
+				catch (InputMismatchException e){
+					System.out.println("[ERROR] 입력 문자의 타입이 맞지 않습니다.");
+					continue;
+				}
+				try {
+					checkNumberValidity(min, max, userAlphabet);
+
+				}
+				catch(Exception e){
+					System.out.println(e.getMessage());
+					continue;
+				}
+				if(answer>userAlphabet){
+					System.out.println("UP");
+					min = (char)(userAlphabet+1);
+					if(min == '[') {
+						min = 'a';
+					}
+				}
+				else if(answer<userAlphabet){
+					System.out.println("DOWN");
+					max = (char)(userAlphabet-1);
+					if(max == '`') {
+						max = 'Z';
+					}
+				}
+				else{
+					System.out.println("정답!");
+				}
+				tryNum++;
+			}
+		}
+		System.out.println("시도한 횟수 : " + tryNum + "회");
+
+	}
+
+
 
-	public static void main(String[] args) {
-		System.out.print("hihi :D");
+	public static void main(String[] args) throws Exception {
+		UpdownApplication app = new UpdownApplication();
+		app.run();
 	}
 }
diff --git a/src/test/java/leets/land/UpdownApplicationTests.java b/src/test/java/leets/land/UpdownApplicationTests.java
index fe61ffe..edaea7e 100644
--- a/src/test/java/leets/land/UpdownApplicationTests.java
+++ b/src/test/java/leets/land/UpdownApplicationTests.java
@@ -1,11 +1,30 @@
 package leets.land;
 
+import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
 class UpdownApplicationTests {
+	UpdownApplication app;
 
+	@BeforeEach
+	void setUp() {
+		app = new UpdownApplication();
+	}
 	@Test
 	void contextLoads() {
 	}
+	@Test
+	void checkNumberValidity(){
+		int min = 40;
+		int max = 60;
+		int userInput = 20;
+
+		assertThrows(Exception.class, ()->{
+			app.checkNumberValidity(min, max, userInput);
+		});
+
+	}
 
 }