import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Scanner;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        B solver = new B();
        solver.solve(1, in, out);
        out.close();
    }

    static class B {
        public void solve(int testNumber, Scanner in, PrintWriter out) {
            // 入力
            String S = in.next();
            int ans = 0;
            int apos = 0;
            int zpos = 0;

            for (int i = 0; i < S.length(); i++) {
                if (S.charAt(i) == 'A') {
                    apos = i;
                    break;
                }
            }

            for (int i = S.length() - 1; i > 1; i--) {
                if (S.charAt(i) == 'Z') {
                    zpos = i + 1;
                    break;
                }
            }

            ans = zpos - apos;

            // 出力
            out.println(ans);

        }

    }
}
 import java.io.OutputStream; OutputStream java.io import java.io.IOException; IOException java.io import java.io.InputStream; InputStream java.io import java.io.PrintWriter; PrintWriter java.io import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        B solver = new B();
        solver.solve(1, in, out);
        out.close();
    }

    static class B {
        public void solve(int testNumber, Scanner in, PrintWriter out) {
            // 入力
            String S = in.next();
            int ans = 0;
            int apos = 0;
            int zpos = 0;

            for (int i = 0; i < S.length(); i++) {
                if (S.charAt(i) == 'A') {
                    apos = i;
                    break;
                }
            }

            for (int i = S.length() - 1; i > 1; i--) {
                if (S.charAt(i) == 'Z') {
                    zpos = i + 1;
                    break;
                }
            }

            ans = zpos - apos;

            // 出力
            out.println(ans);

        }

    }
} Main public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        B solver = new B();
        solver.solve(1, in, out);
        out.close();
    } main {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        B solver = new B();
        solver.solve(1, in, out);
        out.close();
    } InputStream inputStream = System.in; inputStream System.in System System.in OutputStream outputStream = System.out; outputStream System.out System System.out Scanner in = new Scanner(inputStream); in new Scanner(inputStream) PrintWriter out = new PrintWriter(outputStream); out new PrintWriter(outputStream) B solver = new B(); solver new B() solver.solve(1, in, out) solver.solve solver 1 in out out.close() out.close out String[] args args static class B {
        public void solve(int testNumber, Scanner in, PrintWriter out) {
            // 入力
            String S = in.next();
            int ans = 0;
            int apos = 0;
            int zpos = 0;

            for (int i = 0; i < S.length(); i++) {
                if (S.charAt(i) == 'A') {
                    apos = i;
                    break;
                }
            }

            for (int i = S.length() - 1; i > 1; i--) {
                if (S.charAt(i) == 'Z') {
                    zpos = i + 1;
                    break;
                }
            }

            ans = zpos - apos;

            // 出力
            out.println(ans);

        }

    } B public void solve(int testNumber, Scanner in, PrintWriter out) {
            // 入力
            String S = in.next();
            int ans = 0;
            int apos = 0;
            int zpos = 0;

            for (int i = 0; i < S.length(); i++) {
                if (S.charAt(i) == 'A') {
                    apos = i;
                    break;
                }
            }

            for (int i = S.length() - 1; i > 1; i--) {
                if (S.charAt(i) == 'Z') {
                    zpos = i + 1;
                    break;
                }
            }

            ans = zpos - apos;

            // 出力
            out.println(ans);

        } solve {
            // 入力
            String S = in.next();
            int ans = 0;
            int apos = 0;
            int zpos = 0;

            for (int i = 0; i < S.length(); i++) {
                if (S.charAt(i) == 'A') {
                    apos = i;
                    break;
                }
            }

            for (int i = S.length() - 1; i > 1; i--) {
                if (S.charAt(i) == 'Z') {
                    zpos = i + 1;
                    break;
                }
            }

            ans = zpos - apos;

            // 出力
            out.println(ans);

        } String S = in.next(); S in.next() in.next in int ans = 0; ans 0 int apos = 0; apos 0 int zpos = 0; zpos 0 for (int i = 0; i < S.length(); i++) {
                if (S.charAt(i) == 'A') {
                    apos = i;
                    break;
                }
            } int i = 0; int i = 0; i 0 i < S.length() i S.length() S.length S i++ i++ i {
                if (S.charAt(i) == 'A') {
                    apos = i;
                    break;
                }
            } {
                if (S.charAt(i) == 'A') {
                    apos = i;
                    break;
                }
            } if (S.charAt(i) == 'A') {
                    apos = i;
                    break;
                } S.charAt(i) == 'A' S.charAt(i) S.charAt S i 'A' {
                    apos = i;
                    break;
                } apos = i apos i break; for (int i = S.length() - 1; i > 1; i--) {
                if (S.charAt(i) == 'Z') {
                    zpos = i + 1;
                    break;
                }
            } int i = S.length() - 1; int i = S.length() - 1; i S.length() - 1 S.length() S.length S 1 i > 1 i 1 i-- i-- i {
                if (S.charAt(i) == 'Z') {
                    zpos = i + 1;
                    break;
                }
            } {
                if (S.charAt(i) == 'Z') {
                    zpos = i + 1;
                    break;
                }
            } if (S.charAt(i) == 'Z') {
                    zpos = i + 1;
                    break;
                } S.charAt(i) == 'Z' S.charAt(i) S.charAt S i 'Z' {
                    zpos = i + 1;
                    break;
                } zpos = i + 1 zpos i + 1 i 1 break; ans = zpos - apos ans zpos - apos zpos apos out.println(ans) out.println out ans int testNumber testNumber Scanner in in PrintWriter out out public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        B solver = new B();
        solver.solve(1, in, out);
        out.close();
    }

    static class B {
        public void solve(int testNumber, Scanner in, PrintWriter out) {
            // 入力
            String S = in.next();
            int ans = 0;
            int apos = 0;
            int zpos = 0;

            for (int i = 0; i < S.length(); i++) {
                if (S.charAt(i) == 'A') {
                    apos = i;
                    break;
                }
            }

            for (int i = S.length() - 1; i > 1; i--) {
                if (S.charAt(i) == 'Z') {
                    zpos = i + 1;
                    break;
                }
            }

            ans = zpos - apos;

            // 出力
            out.println(ans);

        }

    }
} public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        B solver = new B();
        solver.solve(1, in, out);
        out.close();
    }

    static class B {
        public void solve(int testNumber, Scanner in, PrintWriter out) {
            // 入力
            String S = in.next();
            int ans = 0;
            int apos = 0;
            int zpos = 0;

            for (int i = 0; i < S.length(); i++) {
                if (S.charAt(i) == 'A') {
                    apos = i;
                    break;
                }
            }

            for (int i = S.length() - 1; i > 1; i--) {
                if (S.charAt(i) == 'Z') {
                    zpos = i + 1;
                    break;
                }
            }

            ans = zpos - apos;

            // 出力
            out.println(ans);

        }

    }
} Main
import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Scanner;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        B solver = new B();
        solver.solve(1, in, out);
        out.close();
    }

    static class B {
        public void solve(int testNumber, Scanner in, PrintWriter out) {
            // 入力
            String S = in.next();
            int ans = 0;
            int apos = 0;
            int zpos = 0;

            for (int i = 0; i < S.length(); i++) {
                if (S.charAt(i) == 'A') {
                    apos = i;
                    break;
                }
            }

            for (int i = S.length() - 1; i > 1; i--) {
                if (S.charAt(i) == 'Z') {
                    zpos = i + 1;
                    break;
                }
            }

            ans = zpos - apos;

            // 出力
            out.println(ans);

        }

    }
}

