# link: https://projecteuler.net/problem=28

# 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?
size = 1001
total = 1
n = 1
for x in range(2, size, 2):
    for y in range(0, 4):
        n += x
        total += n
print(total)
