"""
Starting with the number 1 and moving to the right in a clockwise direction a 5 by 5 spiral is formed as follows:
21 22 23 24 25
20  7  8  9 10
19  6  1  2 11
18  5  4  3 12
17 16 15 14 13
It can be verified that the sum of the numbers on the diagonals is 101.

What is the sum of the numbers on the diagonals in a 1001 by 1001 spiral formed in the same way?
"""
from pip._vendor.urllib3.connectionpool import xrange


def numberSpiralDiagonals(diagonals):
    n = 2
    sum = 1
    lastNum = 1
    while n < diagonals+1:
        for i in xrange(4):
            lastNum += n
            sum += lastNum
        n += 2
    return sum

print(numberSpiralDiagonals(1000))
