
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner sc = new Scanner(System.in);
		char A[] = new char[200000];
		A = sc.next().toCharArray();
		int max=1;
		int count=0;
		boolean flag=false;
		for(int i=0;i<A.length;i++){
			if(A[i]=='A'){
				flag=true;
			}
			
			if(A[i]=='Z' && flag){
				count++;
				if(max<count)
				max=count;
			}
			else if(flag){
				count++;
			}
		}
		if(max<=1){System.out.println("0");}
		else{System.out.println(max);}
	
	}
}

/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