import random

nrOfDays = 365
crashesOfAYear = [0] * nrOfDays # A list where each element represents a day

# For each day randomize if it crashes or not.
for i in range(0, nrOfDays):
	if random.randint(1, 8) == 7:
		crashesOfAYear[i] = 1

daysBetweenErrors = []
interval = 0
# Calculate the amount of days between each error.
for i in range(0, nrOfDays):
	interval += 1
	if crashesOfAYear[i] == 1:
		interval = 0
		daysBetweenErrors.append(interval)

# Sums up all amount of days between each error.
sum = 0
for i in range(0, len(daysBetweenErrors)-1):
	sum += daysBetweenErrors[i]

# Calculate the mean value.
print(sum/len(daysBetweenErrors))