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