import java.util.Scanner;

public class Main {

	public static void main (String[] args) {
		Scanner scan = new Scanner(System.in);
		String s = scan.next();
		System.out.println(s.lastIndexOf("Z")-s.indexOf("A")+1);
	}

} import java.util.Scanner; Scanner java.util public class Main {

	public static void main (String[] args) {
		Scanner scan = new Scanner(System.in);
		String s = scan.next();
		System.out.println(s.lastIndexOf("Z")-s.indexOf("A")+1);
	}

} Main public static void main (String[] args) {
		Scanner scan = new Scanner(System.in);
		String s = scan.next();
		System.out.println(s.lastIndexOf("Z")-s.indexOf("A")+1);
	} main {
		Scanner scan = new Scanner(System.in);
		String s = scan.next();
		System.out.println(s.lastIndexOf("Z")-s.indexOf("A")+1);
	} Scanner scan = new Scanner(System.in); scan new Scanner(System.in) String s = scan.next(); s scan.next() scan.next scan 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) {
		Scanner scan = new Scanner(System.in);
		String s = scan.next();
		System.out.println(s.lastIndexOf("Z")-s.indexOf("A")+1);
	}

} public class Main {

	public static void main (String[] args) {
		Scanner scan = new Scanner(System.in);
		String s = scan.next();
		System.out.println(s.lastIndexOf("Z")-s.indexOf("A")+1);
	}

} Main
import java.util.Scanner;

public class Main {

	public static void main (String[] args) {
		Scanner scan = new Scanner(System.in);
		String s = scan.next();
		System.out.println(s.lastIndexOf("Z")-s.indexOf("A")+1);
	}

}