import java.util.Scanner;

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

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

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

		} main {
		Scanner sc = new Scanner(System.in);
		String s = sc.nextLine();
		System.out.println(-s.indexOf("A") +s.lastIndexOf("Z")  + 1);

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

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

		}
} Main
import java.util.Scanner;

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

		}
}