
    Given a patient's n distinct medical risk factors, determine the total number of possible ways these factors can be grouped together to create unique risk assessment profiles, where each risk factor must be included in exactly one group and the order of factors within groups doesn't matter. For example, if monitoring blood pressure, heart rate, and oxygen levels (n=3), find all possible ways to combine these vital signs into risk assessment groups to ensure comprehensive patient readmission evaluation.
    

    
def bell_number(n):
    """
    Given a patient's n distinct medical risk factors, determine the total number of possible ways these factors can be grouped together to create unique risk assessment profiles, where each risk factor must be included in exactly one group and the order of factors within groups doesn't matter. For example, if monitoring blood pressure, heart rate, and oxygen levels (n=3), find all possible ways to combine these vital signs into risk assessment groups to ensure comprehensive patient readmission evaluation.
    

    """
def bell_number(n):
    """
    Given a patient's n distinct medical risk factors, determine the total number of possible ways these factors can be grouped together to create unique risk assessment profiles, where each risk factor must be included in exactly one group and the order of factors within groups doesn't matter. For example, if monitoring blood pressure, heart rate, and oxygen levels (n=3), find all possible ways to combine these vital signs into risk assessment groups to ensure comprehensive patient readmission evaluation.
    

    """
    bell = [[0 for i in range(n + 1)] for j in range(n + 1)]
    bell[0][0] = 1
    for i in range(1, n + 1):
        bell[i][0] = bell[i - 1][i - 1]
        for j in range(1, i + 1):
            bell[i][j] = bell[i - 1][j - 1] + bell[i][j - 1]
    return bell[n][0]