import java.util.Scanner;

public class Main {

	private static final long x = (long) Math.pow(10, 18);

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String s = sc.next();

		System.out.println(s.lastIndexOf('Z') - s.indexOf('A') + 1);

		sc.close();
	}

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

	private static final long x = (long) Math.pow(10, 18);

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String s = sc.next();

		System.out.println(s.lastIndexOf('Z') - s.indexOf('A') + 1);

		sc.close();
	}

} Main private static final long x = (long) Math.pow(10, 18); x (long) Math.pow(10, 18) Math.pow Math 10 18 public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String s = sc.next();

		System.out.println(s.lastIndexOf('Z') - s.indexOf('A') + 1);

		sc.close();
	} main {
		Scanner sc = new Scanner(System.in);
		String s = sc.next();

		System.out.println(s.lastIndexOf('Z') - s.indexOf('A') + 1);

		sc.close();
	} 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 sc.close() sc.close sc String[] args args public class Main {

	private static final long x = (long) Math.pow(10, 18);

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String s = sc.next();

		System.out.println(s.lastIndexOf('Z') - s.indexOf('A') + 1);

		sc.close();
	}

} public class Main {

	private static final long x = (long) Math.pow(10, 18);

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String s = sc.next();

		System.out.println(s.lastIndexOf('Z') - s.indexOf('A') + 1);

		sc.close();
	}

} Main
import java.util.Scanner;

public class Main {

	private static final long x = (long) Math.pow(10, 18);

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String s = sc.next();

		System.out.println(s.lastIndexOf('Z') - s.indexOf('A') + 1);

		sc.close();
	}

}
