import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String s=sc.next();
        int start = 0;
        int end = s.length() -1;
        for (int i = 0; i < s.length(); i++) {
            if (s.charAt(i) == 'A') {
                start = i;
                break;
            }
        }
        for (int i = s.length() - 1; i >= 0; i--) {
            if (s.charAt(i) == 'Z') {
                end = i;
                break;
            }
        }
        System.out.println(end - start + 1);
    }
} import java.util.*; util.* java public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String s=sc.next();
        int start = 0;
        int end = s.length() -1;
        for (int i = 0; i < s.length(); i++) {
            if (s.charAt(i) == 'A') {
                start = i;
                break;
            }
        }
        for (int i = s.length() - 1; i >= 0; i--) {
            if (s.charAt(i) == 'Z') {
                end = i;
                break;
            }
        }
        System.out.println(end - start + 1);
    }
} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String s=sc.next();
        int start = 0;
        int end = s.length() -1;
        for (int i = 0; i < s.length(); i++) {
            if (s.charAt(i) == 'A') {
                start = i;
                break;
            }
        }
        for (int i = s.length() - 1; i >= 0; i--) {
            if (s.charAt(i) == 'Z') {
                end = i;
                break;
            }
        }
        System.out.println(end - start + 1);
    } main {
        Scanner sc = new Scanner(System.in);
        String s=sc.next();
        int start = 0;
        int end = s.length() -1;
        for (int i = 0; i < s.length(); i++) {
            if (s.charAt(i) == 'A') {
                start = i;
                break;
            }
        }
        for (int i = s.length() - 1; i >= 0; i--) {
            if (s.charAt(i) == 'Z') {
                end = i;
                break;
            }
        }
        System.out.println(end - start + 1);
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) String s=sc.next(); s sc.next() sc.next sc int start = 0; start 0 int end = s.length() -1; end s.length() -1 s.length() s.length s 1 for (int i = 0; i < s.length(); i++) {
            if (s.charAt(i) == 'A') {
                start = 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') {
                start = i;
                break;
            }
        } {
            if (s.charAt(i) == 'A') {
                start = i;
                break;
            }
        } if (s.charAt(i) == 'A') {
                start = i;
                break;
            } s.charAt(i) == 'A' s.charAt(i) s.charAt s i 'A' {
                start = i;
                break;
            } start = i start i break; for (int i = s.length() - 1; i >= 0; i--) {
            if (s.charAt(i) == 'Z') {
                end = i;
                break;
            }
        } int i = s.length() - 1; int i = s.length() - 1; i s.length() - 1 s.length() s.length s 1 i >= 0 i 0 i-- i-- i {
            if (s.charAt(i) == 'Z') {
                end = i;
                break;
            }
        } {
            if (s.charAt(i) == 'Z') {
                end = i;
                break;
            }
        } if (s.charAt(i) == 'Z') {
                end = i;
                break;
            } s.charAt(i) == 'Z' s.charAt(i) s.charAt s i 'Z' {
                end = i;
                break;
            } end = i end i break; System.out.println(end - start + 1) System.out.println System.out System System.out end - start + 1 end - start end start 1 String[] args args public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String s=sc.next();
        int start = 0;
        int end = s.length() -1;
        for (int i = 0; i < s.length(); i++) {
            if (s.charAt(i) == 'A') {
                start = i;
                break;
            }
        }
        for (int i = s.length() - 1; i >= 0; i--) {
            if (s.charAt(i) == 'Z') {
                end = i;
                break;
            }
        }
        System.out.println(end - start + 1);
    }
} public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String s=sc.next();
        int start = 0;
        int end = s.length() -1;
        for (int i = 0; i < s.length(); i++) {
            if (s.charAt(i) == 'A') {
                start = i;
                break;
            }
        }
        for (int i = s.length() - 1; i >= 0; i--) {
            if (s.charAt(i) == 'Z') {
                end = i;
                break;
            }
        }
        System.out.println(end - start + 1);
    }
} Main
import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String s=sc.next();
        int start = 0;
        int end = s.length() -1;
        for (int i = 0; i < s.length(); i++) {
            if (s.charAt(i) == 'A') {
                start = i;
                break;
            }
        }
        for (int i = s.length() - 1; i >= 0; i--) {
            if (s.charAt(i) == 'Z') {
                end = i;
                break;
            }
        }
        System.out.println(end - start + 1);
    }
}