
    Design a function for an adaptive learning system that determines the complexity level of a student's written response by calculating the total number of possible meaningful text segments (non-empty substrings) that can be derived from their answer. The system uses this count as one metric to gauge the intricacy of the response and adjust subsequent learning materials accordingly.
    

    
def number_of_substrings(str):
    """
    Design a function for an adaptive learning system that determines the complexity level of a student's written response by calculating the total number of possible meaningful text segments (non-empty substrings) that can be derived from their answer. The system uses this count as one metric to gauge the intricacy of the response and adjust subsequent learning materials accordingly.
    

    """
def number_of_substrings(str):
    """
    Design a function for an adaptive learning system that determines the complexity level of a student's written response by calculating the total number of possible meaningful text segments (non-empty substrings) that can be derived from their answer. The system uses this count as one metric to gauge the intricacy of the response and adjust subsequent learning materials accordingly.
    

    """
    str_len = len(str)
    return int(str_len * (str_len + 1) / 2)