#!/usr/bin/env python3

# quesiton 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?

limit = 1001*1001
#limit = 5*5
jump = 2
i=1
while i <= limit:
  if i==1: 
    total=1
    i = 3
    jump=2
  else:
    for j in range(4):
      #print(i,jump)
      total += i
      i+= jump
    i+=2;jump+=2

print(total)
# correct!
    
