
    Given n delivery zones in a city, determine the number of different ways to organize these zones into distinct route groups for your delivery fleet, where each zone must be assigned to exactly one route group and empty route groups are not allowed. Each unique arrangement of zones into route groups represents a potential fleet deployment strategy that accounts for varying traffic conditions and delivery priorities.
    

    
def bell_number(n):
    """
    Given n delivery zones in a city, determine the number of different ways to organize these zones into distinct route groups for your delivery fleet, where each zone must be assigned to exactly one route group and empty route groups are not allowed. Each unique arrangement of zones into route groups represents a potential fleet deployment strategy that accounts for varying traffic conditions and delivery priorities.
    

    """
def bell_number(n):
    """
    Given n delivery zones in a city, determine the number of different ways to organize these zones into distinct route groups for your delivery fleet, where each zone must be assigned to exactly one route group and empty route groups are not allowed. Each unique arrangement of zones into route groups represents a potential fleet deployment strategy that accounts for varying traffic conditions and delivery priorities.
    

    """
    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]