def zaa(arg):
    
    """
    The function is responsible for choose a size of the vector, hashing by a part of it and then count the number of zeros
    
    input:
    arg (hexadecimal number): The respective hexadecimal number for hashing
    
    Returns:
    zkey (hash-key): The hashing key
    count (int): The number of zeros
    
    """
    size_bucket=4
    binary_string=str(bin(int((arg.replace('\n','')),16))).replace('0b','')
    hash_key=binary_string[:size_bucket]
    zkey=int(hash_key, 2) 
    fnzeros=binary_string[size_bucket:]
    stop=0
    count=0
    while(stop==0 and count<(len(fnzeros)-1)):
        if(fnzeros[count]=='0'):
            count+=1
        if(fnzeros[count]!='0'):
            stop=1
    return (zkey,count)