import java.io.IOException;
import java.util.Comparator;
import java.util.InputMismatchException;
import java.util.TreeMap;

public class Main {
	int n;
	TreeMap<int[], Integer> dp;

	int nim(int[] a) {
		if (dp.containsKey(a)) {
			return dp.get(a);
		}
		if (a[1] == n) {
			return -1;
		}

		int res = -1;
		for (int i = 2; i < n + 1; i++) {
			if (a[i] == 0)
				continue;

			{
				int x = i / 2;
				int y = i - x;
				int[] tmp = copy(a);
				tmp[i]--;
				tmp[x]++;
				tmp[y]++;
				if (nim(tmp) < 0) {
					res = 1;
				}
			}

			if (2 < i) {
				int x = i / 3;
				int y = (i - x) / 2;
				int z = i - x - y;
				int[] tmp = copy(a);
				tmp[i]--;
				tmp[x]++;
				tmp[y]++;
				tmp[z]++;
				if (nim(tmp) < 0) {
					res = 1;
				}
			}
		}

		dp.put(a, res);
		return res;
	}

	int[] copy(int[] a) {
		int n = a.length;
		int[] res = new int[n];
		for (int i = 0; i < n; i++) {
			res[i] = a[i];
		}
		return res;
	}

	void run() {
		MyScanner sc = new MyScanner();

		n = sc.nextInt();
		int[] a = new int[n + 1];
		a[n] = 1;

		Comparator<int[]> cmp = new Comparator<int[]>() {
			@Override
			public int compare(int[] o1, int[] o2) {
				int n = o1.length;
				if (n != o2.length) {
					return n - o2.length;
				}
				for (int i = 0; i < n; i++) {
					if (o1[i] != o2[i]) {
						return o1[i] - o2[i];
					}
				}
				return 0;
			}
		};

		dp = new TreeMap<int[], Integer>(cmp);
		System.out.println(nim(a) > 0 ? "A" : "B");
	}

	public static void main(String[] args) {
		new Main().run();
	}

	public void mapDebug(int[][] a) {
		System.out.println("--------map display---------");
		for (int i = 0; i < a.length; i++) {
			for (int j = 0; j < a[i].length; j++) {
				System.out.printf("%3d ", a[i][j]);
			}
			System.out.println();
		}
		System.out.println("----------------------------" + '\n');
	}

	class MyScanner {
		int read() {
			try {
				return System.in.read();
			} catch (IOException e) {
				throw new InputMismatchException();
			}
		}

		boolean isSpaceChar(int c) {
			return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
		}

		boolean isEndline(int c) {
			return c == '\n' || c == '\r' || c == -1;
		}

		int nextInt() {
			return Integer.parseInt(next());
		}

		int[] nextIntArray(int n) {
			int[] array = new int[n];
			for (int i = 0; i < n; i++)
				array[i] = nextInt();
			return array;
		}

		long nextLong() {
			return Long.parseLong(next());
		}

		long[] nextLongArray(int n) {
			long[] array = new long[n];
			for (int i = 0; i < n; i++)
				array[i] = nextLong();
			return array;
		}

		double nextDouble() {
			return Double.parseDouble(next());
		}

		double[] nextDoubleArray(int n) {
			double[] array = new double[n];
			for (int i = 0; i < n; i++)
				array[i] = nextDouble();
			return array;
		}

		String next() {
			int c = read();
			while (isSpaceChar(c))
				c = read();
			StringBuilder res = new StringBuilder();
			do {
				res.appendCodePoint(c);
				c = read();
			} while (!isSpaceChar(c));
			return res.toString();
		}

		String[] nextStringArray(int n) {
			String[] array = new String[n];
			for (int i = 0; i < n; i++)
				array[i] = next();

			return array;
		}

		String nextLine() {
			int c = read();
			while (isEndline(c))
				c = read();
			StringBuilder res = new StringBuilder();
			do {
				res.appendCodePoint(c);
				c = read();
			} while (!isEndline(c));
			return res.toString();
		}
	}
}