import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		try (Scanner scanner = new Scanner(System.in)) {
			int N = scanner.nextInt();
			Map<Integer, Integer> map = new HashMap<Integer, Integer>();

			for (int i = 0; i < N; i++) {
				int key = scanner.nextInt();
				if (map.containsKey(key)) {
					;
				} else {
					map.put(key, 1);
				}
			}
			System.out.println(map.size());
		}
	}
} import java.util.HashMap; HashMap java.util import java.util.Map; Map java.util import java.util.Scanner; Scanner java.util public class Main {
	public static void main(String[] args) {
		try (Scanner scanner = new Scanner(System.in)) {
			int N = scanner.nextInt();
			Map<Integer, Integer> map = new HashMap<Integer, Integer>();

			for (int i = 0; i < N; i++) {
				int key = scanner.nextInt();
				if (map.containsKey(key)) {
					;
				} else {
					map.put(key, 1);
				}
			}
			System.out.println(map.size());
		}
	}
} Main public static void main(String[] args) {
		try (Scanner scanner = new Scanner(System.in)) {
			int N = scanner.nextInt();
			Map<Integer, Integer> map = new HashMap<Integer, Integer>();

			for (int i = 0; i < N; i++) {
				int key = scanner.nextInt();
				if (map.containsKey(key)) {
					;
				} else {
					map.put(key, 1);
				}
			}
			System.out.println(map.size());
		}
	} main {
		try (Scanner scanner = new Scanner(System.in)) {
			int N = scanner.nextInt();
			Map<Integer, Integer> map = new HashMap<Integer, Integer>();

			for (int i = 0; i < N; i++) {
				int key = scanner.nextInt();
				if (map.containsKey(key)) {
					;
				} else {
					map.put(key, 1);
				}
			}
			System.out.println(map.size());
		}
	} try (Scanner scanner = new Scanner(System.in)) {
			int N = scanner.nextInt();
			Map<Integer, Integer> map = new HashMap<Integer, Integer>();

			for (int i = 0; i < N; i++) {
				int key = scanner.nextInt();
				if (map.containsKey(key)) {
					;
				} else {
					map.put(key, 1);
				}
			}
			System.out.println(map.size());
		} {
			int N = scanner.nextInt();
			Map<Integer, Integer> map = new HashMap<Integer, Integer>();

			for (int i = 0; i < N; i++) {
				int key = scanner.nextInt();
				if (map.containsKey(key)) {
					;
				} else {
					map.put(key, 1);
				}
			}
			System.out.println(map.size());
		} Scanner scanner = new Scanner(System.in) Scanner scanner = new Scanner(System.in) new Scanner(System.in) int N = scanner.nextInt(); N scanner.nextInt() scanner.nextInt scanner Map<Integer, Integer> map = new HashMap<Integer, Integer>(); map new HashMap<Integer, Integer>() for (int i = 0; i < N; i++) {
				int key = scanner.nextInt();
				if (map.containsKey(key)) {
					;
				} else {
					map.put(key, 1);
				}
			} int i = 0; int i = 0; i 0 i < N i N i++ i++ i {
				int key = scanner.nextInt();
				if (map.containsKey(key)) {
					;
				} else {
					map.put(key, 1);
				}
			} {
				int key = scanner.nextInt();
				if (map.containsKey(key)) {
					;
				} else {
					map.put(key, 1);
				}
			} int key = scanner.nextInt(); key scanner.nextInt() scanner.nextInt scanner if (map.containsKey(key)) {
					;
				} else {
					map.put(key, 1);
				} map.containsKey(key) map.containsKey map key {
					;
				} {
					map.put(key, 1);
				} map.put(key, 1) map.put map key 1 System.out.println(map.size()) System.out.println System.out System System.out map.size() map.size map String[] args args public class Main {
	public static void main(String[] args) {
		try (Scanner scanner = new Scanner(System.in)) {
			int N = scanner.nextInt();
			Map<Integer, Integer> map = new HashMap<Integer, Integer>();

			for (int i = 0; i < N; i++) {
				int key = scanner.nextInt();
				if (map.containsKey(key)) {
					;
				} else {
					map.put(key, 1);
				}
			}
			System.out.println(map.size());
		}
	}
} public class Main {
	public static void main(String[] args) {
		try (Scanner scanner = new Scanner(System.in)) {
			int N = scanner.nextInt();
			Map<Integer, Integer> map = new HashMap<Integer, Integer>();

			for (int i = 0; i < N; i++) {
				int key = scanner.nextInt();
				if (map.containsKey(key)) {
					;
				} else {
					map.put(key, 1);
				}
			}
			System.out.println(map.size());
		}
	}
} Main
import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		try (Scanner scanner = new Scanner(System.in)) {
			int N = scanner.nextInt();
			Map<Integer, Integer> map = new HashMap<Integer, Integer>();

			for (int i = 0; i < N; i++) {
				int key = scanner.nextInt();
				if (map.containsKey(key)) {
					;
				} else {
					map.put(key, 1);
				}
			}
			System.out.println(map.size());
		}
	}
}