import java.util.*;
import java.io.*;
import java.math.*;
 
public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        String s = sc.next();
        System.out.println(s.lastIndexOf("Z") - s.indexOf("A")+1);
    }
} import java.util.*; util.* java import java.io.*; io.* java import java.math.*; math.* java public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        String s = sc.next();
        System.out.println(s.lastIndexOf("Z") - s.indexOf("A")+1);
    }
} Main public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        String s = sc.next();
        System.out.println(s.lastIndexOf("Z") - s.indexOf("A")+1);
    } main {
        Scanner sc = new Scanner(System.in);
        String s = sc.next();
        System.out.println(s.lastIndexOf("Z") - s.indexOf("A")+1);
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) String s = sc.next(); s sc.next() sc.next sc System.out.println(s.lastIndexOf("Z") - s.indexOf("A")+1) System.out.println System.out System System.out s.lastIndexOf("Z") - s.indexOf("A")+1 s.lastIndexOf("Z") - s.indexOf("A") s.lastIndexOf("Z") s.lastIndexOf s "Z" s.indexOf("A") s.indexOf s "A" 1 String[] args args public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        String s = sc.next();
        System.out.println(s.lastIndexOf("Z") - s.indexOf("A")+1);
    }
} public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        String s = sc.next();
        System.out.println(s.lastIndexOf("Z") - s.indexOf("A")+1);
    }
} Main
import java.util.*;
import java.io.*;
import java.math.*;
 
public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        String s = sc.next();
        System.out.println(s.lastIndexOf("Z") - s.indexOf("A")+1);
    }
}