
import java.io.*;
import java.util.*;
//import java.util.Map.Entry;
//import java.util.stream.*;
//import java.math.*;

public class Main {

    public static int gcd(int a, int b) {
        return (b == 0) ? a : gcd(b, a % b);
    }

    public static void main(String[] args) throws IOException {

        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
        Scanner sc = new Scanner(System.in);
        char c = br.readLine().charAt(0);
        int num = (int) c;
        System.out.println(c <= 122 && c >= 97 ? "a" : "A"
        );
        bw.flush();
    }
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    static class Pair implements Comparable<Pair> {

        int a, b;

        public Pair(int x, int y) {
            a = x;
            b = y;
        }

        @Override
        public int compareTo(Pair p) {
            return a - p.a;
        }
    }

    static void forl_0(int n, int[] array, Scanner sc) {
        for (int i = 0; i < n; i++) {
            array[i] = sc.nextInt();
        }
    }

    static void forl_1(int n, int[] array, Scanner sc) {
        for (int i = 1; i <= n; i++) {
            array[i] = sc.nextInt();
        }
    }

    static void two_d(int n, int m, int[][] array, Scanner sc) {
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < m; j++) {
                array[i][j] = sc.nextInt();
            }
        }
    }

    static boolean isPrime(long n) {
        if (n < 2) {
            return false;
        } else if (n == 2 || n == 3) {
            return true;
        } else if (n % 2 == 0 || n % 3 == 0) {
            return false;
        }
        long sqrtN = (long) Math.sqrt(n) + 1;
        for (long i = 6L; i <= sqrtN; i += 6) {
            if (n % (i - 1) == 0 || n % (i + 1) == 0) {
                return false;
            }
        }
        return true;
    }
} import java.io.*; io.* java import java.util.*; util.* java public class Main {

    public static int gcd(int a, int b) {
        return (b == 0) ? a : gcd(b, a % b);
    }

    public static void main(String[] args) throws IOException {

        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
        Scanner sc = new Scanner(System.in);
        char c = br.readLine().charAt(0);
        int num = (int) c;
        System.out.println(c <= 122 && c >= 97 ? "a" : "A"
        );
        bw.flush();
    }
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    static class Pair implements Comparable<Pair> {

        int a, b;

        public Pair(int x, int y) {
            a = x;
            b = y;
        }

        @Override
        public int compareTo(Pair p) {
            return a - p.a;
        }
    }

    static void forl_0(int n, int[] array, Scanner sc) {
        for (int i = 0; i < n; i++) {
            array[i] = sc.nextInt();
        }
    }

    static void forl_1(int n, int[] array, Scanner sc) {
        for (int i = 1; i <= n; i++) {
            array[i] = sc.nextInt();
        }
    }

    static void two_d(int n, int m, int[][] array, Scanner sc) {
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < m; j++) {
                array[i][j] = sc.nextInt();
            }
        }
    }

    static boolean isPrime(long n) {
        if (n < 2) {
            return false;
        } else if (n == 2 || n == 3) {
            return true;
        } else if (n % 2 == 0 || n % 3 == 0) {
            return false;
        }
        long sqrtN = (long) Math.sqrt(n) + 1;
        for (long i = 6L; i <= sqrtN; i += 6) {
            if (n % (i - 1) == 0 || n % (i + 1) == 0) {
                return false;
            }
        }
        return true;
    }
} Main public static int gcd(int a, int b) {
        return (b == 0) ? a : gcd(b, a % b);
    } gcd {
        return (b == 0) ? a : gcd(b, a % b);
    } return (b == 0) ? a : gcd(b, a % b); (b == 0) ? a : gcd(b, a % b) (b == 0) b 0 a gcd(b, a % b) gcd b a % b a b int a a int b b public static void main(String[] args) throws IOException {

        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
        Scanner sc = new Scanner(System.in);
        char c = br.readLine().charAt(0);
        int num = (int) c;
        System.out.println(c <= 122 && c >= 97 ? "a" : "A"
        );
        bw.flush();
    } main {

        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
        Scanner sc = new Scanner(System.in);
        char c = br.readLine().charAt(0);
        int num = (int) c;
        System.out.println(c <= 122 && c >= 97 ? "a" : "A"
        );
        bw.flush();
    } BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); br new BufferedReader(new InputStreamReader(System.in)) BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out)); bw new BufferedWriter(new OutputStreamWriter(System.out)) Scanner sc = new Scanner(System.in); sc new Scanner(System.in) char c = br.readLine().charAt(0); c br.readLine().charAt(0) br.readLine().charAt br.readLine() br.readLine br 0 int num = (int) c; num (int) c System.out.println(c <= 122 && c >= 97 ? "a" : "A"
        ) System.out.println System.out System System.out c <= 122 && c >= 97 ? "a" : "A" c <= 122 && c >= 97 c <= 122 c 122 c >= 97 c 97 "a" "A" bw.flush() bw.flush bw String[] args args static void forl_0(int n, int[] array, Scanner sc) {
        for (int i = 0; i < n; i++) {
            array[i] = sc.nextInt();
        }
    } forl_0 {
        for (int i = 0; i < n; i++) {
            array[i] = sc.nextInt();
        }
    } for (int i = 0; i < n; i++) {
            array[i] = sc.nextInt();
        } int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
            array[i] = sc.nextInt();
        } {
            array[i] = sc.nextInt();
        } array[i] = sc.nextInt() array[i] array i sc.nextInt() sc.nextInt sc int n n int[] array array Scanner sc sc static void forl_1(int n, int[] array, Scanner sc) {
        for (int i = 1; i <= n; i++) {
            array[i] = sc.nextInt();
        }
    } forl_1 {
        for (int i = 1; i <= n; i++) {
            array[i] = sc.nextInt();
        }
    } for (int i = 1; i <= n; i++) {
            array[i] = sc.nextInt();
        } int i = 1; int i = 1; i 1 i <= n i n i++ i++ i {
            array[i] = sc.nextInt();
        } {
            array[i] = sc.nextInt();
        } array[i] = sc.nextInt() array[i] array i sc.nextInt() sc.nextInt sc int n n int[] array array Scanner sc sc static void two_d(int n, int m, int[][] array, Scanner sc) {
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < m; j++) {
                array[i][j] = sc.nextInt();
            }
        }
    } two_d {
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < m; j++) {
                array[i][j] = sc.nextInt();
            }
        }
    } for (int i = 0; i < n; i++) {
            for (int j = 0; j < m; j++) {
                array[i][j] = sc.nextInt();
            }
        } int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
            for (int j = 0; j < m; j++) {
                array[i][j] = sc.nextInt();
            }
        } {
            for (int j = 0; j < m; j++) {
                array[i][j] = sc.nextInt();
            }
        } for (int j = 0; j < m; j++) {
                array[i][j] = sc.nextInt();
            } int j = 0; int j = 0; j 0 j < m j m j++ j++ j {
                array[i][j] = sc.nextInt();
            } {
                array[i][j] = sc.nextInt();
            } array[i][j] = sc.nextInt() array[i][j] array[i] array i j sc.nextInt() sc.nextInt sc int n n int m m int[][] array array Scanner sc sc static boolean isPrime(long n) {
        if (n < 2) {
            return false;
        } else if (n == 2 || n == 3) {
            return true;
        } else if (n % 2 == 0 || n % 3 == 0) {
            return false;
        }
        long sqrtN = (long) Math.sqrt(n) + 1;
        for (long i = 6L; i <= sqrtN; i += 6) {
            if (n % (i - 1) == 0 || n % (i + 1) == 0) {
                return false;
            }
        }
        return true;
    } isPrime {
        if (n < 2) {
            return false;
        } else if (n == 2 || n == 3) {
            return true;
        } else if (n % 2 == 0 || n % 3 == 0) {
            return false;
        }
        long sqrtN = (long) Math.sqrt(n) + 1;
        for (long i = 6L; i <= sqrtN; i += 6) {
            if (n % (i - 1) == 0 || n % (i + 1) == 0) {
                return false;
            }
        }
        return true;
    } if (n < 2) {
            return false;
        } else if (n == 2 || n == 3) {
            return true;
        } else if (n % 2 == 0 || n % 3 == 0) {
            return false;
        } n < 2 n 2 {
            return false;
        } return false; false if (n == 2 || n == 3) {
            return true;
        } else if (n % 2 == 0 || n % 3 == 0) {
            return false;
        } n == 2 || n == 3 n == 2 n 2 n == 3 n 3 {
            return true;
        } return true; true if (n % 2 == 0 || n % 3 == 0) {
            return false;
        } n % 2 == 0 || n % 3 == 0 n % 2 == 0 n % 2 n 2 0 n % 3 == 0 n % 3 n 3 0 {
            return false;
        } return false; false long sqrtN = (long) Math.sqrt(n) + 1; sqrtN (long) Math.sqrt(n) + 1 (long) Math.sqrt(n) Math.sqrt Math n 1 for (long i = 6L; i <= sqrtN; i += 6) {
            if (n % (i - 1) == 0 || n % (i + 1) == 0) {
                return false;
            }
        } long i = 6L; long i = 6L; i 6L i <= sqrtN i sqrtN i += 6 i += 6 i 6 {
            if (n % (i - 1) == 0 || n % (i + 1) == 0) {
                return false;
            }
        } {
            if (n % (i - 1) == 0 || n % (i + 1) == 0) {
                return false;
            }
        } if (n % (i - 1) == 0 || n % (i + 1) == 0) {
                return false;
            } n % (i - 1) == 0 || n % (i + 1) == 0 n % (i - 1) == 0 n % (i - 1) n (i - 1) i 1 0 n % (i + 1) == 0 n % (i + 1) n (i + 1) i 1 0 {
                return false;
            } return false; false return true; true long n n static class Pair implements Comparable<Pair> {

        int a, b;

        public Pair(int x, int y) {
            a = x;
            b = y;
        }

        @Override
        public int compareTo(Pair p) {
            return a - p.a;
        }
    } Pair int a a b; b public Pair(int x, int y) {
            a = x;
            b = y;
        } Pair {
            a = x;
            b = y;
        } a = x a x b = y b y int x x int y y @Override
        public int compareTo(Pair p) {
            return a - p.a;
        } compareTo {
            return a - p.a;
        } return a - p.a; a - p.a a p.a p p.a Pair p p Comparable public class Main {

    public static int gcd(int a, int b) {
        return (b == 0) ? a : gcd(b, a % b);
    }

    public static void main(String[] args) throws IOException {

        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
        Scanner sc = new Scanner(System.in);
        char c = br.readLine().charAt(0);
        int num = (int) c;
        System.out.println(c <= 122 && c >= 97 ? "a" : "A"
        );
        bw.flush();
    }
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//==============================================//

    static class Pair implements Comparable<Pair> {

        int a, b;

        public Pair(int x, int y) {
            a = x;
            b = y;
        }

        @Override
        public int compareTo(Pair p) {
            return a - p.a;
        }
    }

    static void forl_0(int n, int[] array, Scanner sc) {
        for (int i = 0; i < n; i++) {
            array[i] = sc.nextInt();
        }
    }

    static void forl_1(int n, int[] array, Scanner sc) {
        for (int i = 1; i <= n; i++) {
            array[i] = sc.nextInt();
        }
    }

    static void two_d(int n, int m, int[][] array, Scanner sc) {
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < m; j++) {
                array[i][j] = sc.nextInt();
            }
        }
    }

    static boolean isPrime(long n) {
        if (n < 2) {
            return false;
        } else if (n == 2 || n == 3) {
            return true;
        } else if (n % 2 == 0 || n % 3 == 0) {
            return false;
        }
        long sqrtN = (long) Math.sqrt(n) + 1;
        for (long i = 6L; i <= sqrtN; i += 6) {
            if (n % (i - 1) == 0 || n % (i + 1) == 0) {
                return false;
            }
        }
        return true;
    }
} public class Main {

    public static int gcd(int a, int b) {
        return (b == 0) ? a : gcd(b, a % b);
    }

    public static void main(String[] args) throws IOException {

        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
        Scanner sc = new Scanner(System.in);
        char c = br.readLine().charAt(0);
        int num = (int) c;
        System.out.println(c <= 122 && c >= 97 ? "a" : "A"
        );
        bw.flush();
    }
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//==============================================//

    static class Pair implements Comparable<Pair> {

        int a, b;

        public Pair(int x, int y) {
            a = x;
            b = y;
        }

        @Override
        public int compareTo(Pair p) {
            return a - p.a;
        }
    }

    static void forl_0(int n, int[] array, Scanner sc) {
        for (int i = 0; i < n; i++) {
            array[i] = sc.nextInt();
        }
    }

    static void forl_1(int n, int[] array, Scanner sc) {
        for (int i = 1; i <= n; i++) {
            array[i] = sc.nextInt();
        }
    }

    static void two_d(int n, int m, int[][] array, Scanner sc) {
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < m; j++) {
                array[i][j] = sc.nextInt();
            }
        }
    }

    static boolean isPrime(long n) {
        if (n < 2) {
            return false;
        } else if (n == 2 || n == 3) {
            return true;
        } else if (n % 2 == 0 || n % 3 == 0) {
            return false;
        }
        long sqrtN = (long) Math.sqrt(n) + 1;
        for (long i = 6L; i <= sqrtN; i += 6) {
            if (n % (i - 1) == 0 || n % (i + 1) == 0) {
                return false;
            }
        }
        return true;
    }
} Main

import java.io.*;
import java.util.*;
//import java.util.Map.Entry;
//import java.util.stream.*;
//import java.math.*;

public class Main {

    public static int gcd(int a, int b) {
        return (b == 0) ? a : gcd(b, a % b);
    }

    public static void main(String[] args) throws IOException {

        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
        Scanner sc = new Scanner(System.in);
        char c = br.readLine().charAt(0);
        int num = (int) c;
        System.out.println(c <= 122 && c >= 97 ? "a" : "A"
        );
        bw.flush();
    }
//==============================================//
//==============================================//
//==============================================//
//==============================================//
//==============================================//
//==============================================//
//==============================================//
//==============================================//

    static class Pair implements Comparable<Pair> {

        int a, b;

        public Pair(int x, int y) {
            a = x;
            b = y;
        }

        @Override
        public int compareTo(Pair p) {
            return a - p.a;
        }
    }

    static void forl_0(int n, int[] array, Scanner sc) {
        for (int i = 0; i < n; i++) {
            array[i] = sc.nextInt();
        }
    }

    static void forl_1(int n, int[] array, Scanner sc) {
        for (int i = 1; i <= n; i++) {
            array[i] = sc.nextInt();
        }
    }

    static void two_d(int n, int m, int[][] array, Scanner sc) {
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < m; j++) {
                array[i][j] = sc.nextInt();
            }
        }
    }

    static boolean isPrime(long n) {
        if (n < 2) {
            return false;
        } else if (n == 2 || n == 3) {
            return true;
        } else if (n % 2 == 0 || n % 3 == 0) {
            return false;
        }
        long sqrtN = (long) Math.sqrt(n) + 1;
        for (long i = 6L; i <= sqrtN; i += 6) {
            if (n % (i - 1) == 0 || n % (i + 1) == 0) {
                return false;
            }
        }
        return true;
    }
}
