

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        while (sc.hasNext()) {
            char[] s = sc.next().toCharArray();
            int left = 0;
            while (s[left] != 'A') {
                left++;
            }

            int right = s.length - 1;
            while (s[right] != 'Z') {
                right--;
            }

            System.out.println(right - left + 1);
        }
    }
}

/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz