import java.util.Scanner;

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

		int firstIndex = s.indexOf('A');
		int lastIndex = s.lastIndexOf('Z');

		int result = lastIndex - firstIndex +1;
		System.out.println(result);

	}

} 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();

		int firstIndex = s.indexOf('A');
		int lastIndex = s.lastIndexOf('Z');

		int result = lastIndex - firstIndex +1;
		System.out.println(result);

	}

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

		int firstIndex = s.indexOf('A');
		int lastIndex = s.lastIndexOf('Z');

		int result = lastIndex - firstIndex +1;
		System.out.println(result);

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

		int firstIndex = s.indexOf('A');
		int lastIndex = s.lastIndexOf('Z');

		int result = lastIndex - firstIndex +1;
		System.out.println(result);

	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) String s = sc.nextLine(); s sc.nextLine() sc.nextLine 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' int result = lastIndex - firstIndex +1; result lastIndex - firstIndex +1 lastIndex - firstIndex lastIndex firstIndex 1 System.out.println(result) System.out.println System.out System System.out result String[] args args public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String s = sc.nextLine();

		int firstIndex = s.indexOf('A');
		int lastIndex = s.lastIndexOf('Z');

		int result = lastIndex - firstIndex +1;
		System.out.println(result);

	}

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

		int firstIndex = s.indexOf('A');
		int lastIndex = s.lastIndexOf('Z');

		int result = lastIndex - firstIndex +1;
		System.out.println(result);

	}

} Main
import java.util.Scanner;

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

		int firstIndex = s.indexOf('A');
		int lastIndex = s.lastIndexOf('Z');

		int result = lastIndex - firstIndex +1;
		System.out.println(result);

	}

}
