import java.util.Scanner;

public class Main {
	public static void main (String[] args) {
//------------------------------------------------------------

		Scanner sc =new Scanner(System.in);
		String s = sc.nextLine();
		sc.close();

		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 sc =new Scanner(System.in);
		String s = sc.nextLine();
		sc.close();

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


//------------------------------------------------------------
	}
} Main public static void main (String[] args) {
//------------------------------------------------------------

		Scanner sc =new Scanner(System.in);
		String s = sc.nextLine();
		sc.close();

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


//------------------------------------------------------------
	} main {
//------------------------------------------------------------

		Scanner sc =new Scanner(System.in);
		String s = sc.nextLine();
		sc.close();

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


//------------------------------------------------------------
	} Scanner sc =new Scanner(System.in); sc new Scanner(System.in) String s = sc.nextLine(); s sc.nextLine() sc.nextLine sc sc.close() sc.close 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) {
//------------------------------------------------------------

		Scanner sc =new Scanner(System.in);
		String s = sc.nextLine();
		sc.close();

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


//------------------------------------------------------------
	}
} public class Main {
	public static void main (String[] args) {
//------------------------------------------------------------

		Scanner sc =new Scanner(System.in);
		String s = sc.nextLine();
		sc.close();

		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 sc =new Scanner(System.in);
		String s = sc.nextLine();
		sc.close();

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


//------------------------------------------------------------
	}
}