import random
from itertools import permutations
alltours = permutations

def distance_tour(aTour):
    return sum(distance_points(aTour[i - 1], aTour[i]) for i in range(len(aTour)))

aCity = complex

def distance_points(first, second): return abs(first - second)

def generate_cities(number_of_cities):
    seed = 111
    width = 500
    height = 300
    random.seed((number_of_cities, seed))
    return frozenset(aCity(random.randint(1, width), random.randint(1, height)) 
                     for c in range(number_of_cities))