import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.StringTokenizer;

public class Main {
    static class FastReader {
        BufferedReader br;
        StringTokenizer st;

        FastReader() {
            br = new BufferedReader(new InputStreamReader(System.in));
        }

        String next() {
            while (st == null || !st.hasMoreElements()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

        String nextLine() {
            String str = "";
            try {
                str = br.readLine();
            } catch (Exception e) {
                e.printStackTrace();
            }
            return str;
        }

        int nextInt() {
            return Integer.parseInt(next());
        }
        long nextLong() { return Long.parseLong(next());  }
    }

    public static void main(String[] args) {
        FastReader sn = new FastReader();
        char []c = sn.next().toCharArray();
        if(c[0] >= 'A' && c[0] <= 'Z'){
            System.out.println("A");
        }else
            System.out.println("a");
    }
} import java.io.BufferedReader; BufferedReader java.io import java.io.InputStreamReader; InputStreamReader java.io import java.util.StringTokenizer; StringTokenizer java.util public class Main {
    static class FastReader {
        BufferedReader br;
        StringTokenizer st;

        FastReader() {
            br = new BufferedReader(new InputStreamReader(System.in));
        }

        String next() {
            while (st == null || !st.hasMoreElements()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

        String nextLine() {
            String str = "";
            try {
                str = br.readLine();
            } catch (Exception e) {
                e.printStackTrace();
            }
            return str;
        }

        int nextInt() {
            return Integer.parseInt(next());
        }
        long nextLong() { return Long.parseLong(next());  }
    }

    public static void main(String[] args) {
        FastReader sn = new FastReader();
        char []c = sn.next().toCharArray();
        if(c[0] >= 'A' && c[0] <= 'Z'){
            System.out.println("A");
        }else
            System.out.println("a");
    }
} Main public static void main(String[] args) {
        FastReader sn = new FastReader();
        char []c = sn.next().toCharArray();
        if(c[0] >= 'A' && c[0] <= 'Z'){
            System.out.println("A");
        }else
            System.out.println("a");
    } main {
        FastReader sn = new FastReader();
        char []c = sn.next().toCharArray();
        if(c[0] >= 'A' && c[0] <= 'Z'){
            System.out.println("A");
        }else
            System.out.println("a");
    } FastReader sn = new FastReader(); sn new FastReader() char []c = sn.next().toCharArray(); c sn.next().toCharArray() sn.next().toCharArray sn.next() sn.next sn if(c[0] >= 'A' && c[0] <= 'Z'){
            System.out.println("A");
        }else
            System.out.println("a"); c[0] >= 'A' && c[0] <= 'Z' c[0] >= 'A' c[0] c 0 'A' c[0] <= 'Z' c[0] c 0 'Z' {
            System.out.println("A");
        } System.out.println("A") System.out.println System.out System System.out "A" System.out.println("a") System.out.println System.out System System.out "a" String[] args args static class FastReader {
        BufferedReader br;
        StringTokenizer st;

        FastReader() {
            br = new BufferedReader(new InputStreamReader(System.in));
        }

        String next() {
            while (st == null || !st.hasMoreElements()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

        String nextLine() {
            String str = "";
            try {
                str = br.readLine();
            } catch (Exception e) {
                e.printStackTrace();
            }
            return str;
        }

        int nextInt() {
            return Integer.parseInt(next());
        }
        long nextLong() { return Long.parseLong(next());  }
    } FastReader BufferedReader br; br StringTokenizer st; st FastReader() {
            br = new BufferedReader(new InputStreamReader(System.in));
        } FastReader {
            br = new BufferedReader(new InputStreamReader(System.in));
        } br = new BufferedReader(new InputStreamReader(System.in)) br new BufferedReader(new InputStreamReader(System.in)) String next() {
            while (st == null || !st.hasMoreElements()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        } next {
            while (st == null || !st.hasMoreElements()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        } while (st == null || !st.hasMoreElements()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (Exception e) {
                    e.printStackTrace();
                }
            } st == null || !st.hasMoreElements() st == null st null !st.hasMoreElements() st.hasMoreElements() st.hasMoreElements st {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (Exception e) {
                    e.printStackTrace();
                }
            } try {
                    st = new StringTokenizer(br.readLine());
                } catch (Exception e) {
                    e.printStackTrace();
                } catch (Exception e) {
                    e.printStackTrace();
                } Exception e {
                    e.printStackTrace();
                } e.printStackTrace() e.printStackTrace e {
                    st = new StringTokenizer(br.readLine());
                } st = new StringTokenizer(br.readLine()) st new StringTokenizer(br.readLine()) return st.nextToken(); st.nextToken() st.nextToken st String nextLine() {
            String str = "";
            try {
                str = br.readLine();
            } catch (Exception e) {
                e.printStackTrace();
            }
            return str;
        } nextLine {
            String str = "";
            try {
                str = br.readLine();
            } catch (Exception e) {
                e.printStackTrace();
            }
            return str;
        } String str = ""; str "" try {
                str = br.readLine();
            } catch (Exception e) {
                e.printStackTrace();
            } catch (Exception e) {
                e.printStackTrace();
            } Exception e {
                e.printStackTrace();
            } e.printStackTrace() e.printStackTrace e {
                str = br.readLine();
            } str = br.readLine() str br.readLine() br.readLine br return str; str int nextInt() {
            return Integer.parseInt(next());
        } nextInt {
            return Integer.parseInt(next());
        } return Integer.parseInt(next()); Integer.parseInt(next()) Integer.parseInt Integer next() next long nextLong() { return Long.parseLong(next());  } nextLong { return Long.parseLong(next());  } return Long.parseLong(next()); Long.parseLong(next()) Long.parseLong Long next() next public class Main {
    static class FastReader {
        BufferedReader br;
        StringTokenizer st;

        FastReader() {
            br = new BufferedReader(new InputStreamReader(System.in));
        }

        String next() {
            while (st == null || !st.hasMoreElements()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

        String nextLine() {
            String str = "";
            try {
                str = br.readLine();
            } catch (Exception e) {
                e.printStackTrace();
            }
            return str;
        }

        int nextInt() {
            return Integer.parseInt(next());
        }
        long nextLong() { return Long.parseLong(next());  }
    }

    public static void main(String[] args) {
        FastReader sn = new FastReader();
        char []c = sn.next().toCharArray();
        if(c[0] >= 'A' && c[0] <= 'Z'){
            System.out.println("A");
        }else
            System.out.println("a");
    }
} public class Main {
    static class FastReader {
        BufferedReader br;
        StringTokenizer st;

        FastReader() {
            br = new BufferedReader(new InputStreamReader(System.in));
        }

        String next() {
            while (st == null || !st.hasMoreElements()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

        String nextLine() {
            String str = "";
            try {
                str = br.readLine();
            } catch (Exception e) {
                e.printStackTrace();
            }
            return str;
        }

        int nextInt() {
            return Integer.parseInt(next());
        }
        long nextLong() { return Long.parseLong(next());  }
    }

    public static void main(String[] args) {
        FastReader sn = new FastReader();
        char []c = sn.next().toCharArray();
        if(c[0] >= 'A' && c[0] <= 'Z'){
            System.out.println("A");
        }else
            System.out.println("a");
    }
} Main
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.StringTokenizer;

public class Main {
    static class FastReader {
        BufferedReader br;
        StringTokenizer st;

        FastReader() {
            br = new BufferedReader(new InputStreamReader(System.in));
        }

        String next() {
            while (st == null || !st.hasMoreElements()) {
                try {
                    st = new StringTokenizer(br.readLine());
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
            return st.nextToken();
        }

        String nextLine() {
            String str = "";
            try {
                str = br.readLine();
            } catch (Exception e) {
                e.printStackTrace();
            }
            return str;
        }

        int nextInt() {
            return Integer.parseInt(next());
        }
        long nextLong() { return Long.parseLong(next());  }
    }

    public static void main(String[] args) {
        FastReader sn = new FastReader();
        char []c = sn.next().toCharArray();
        if(c[0] >= 'A' && c[0] <= 'Z'){
            System.out.println("A");
        }else
            System.out.println("a");
    }
}