    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++;
    			}
    		}
    		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