# 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?

lastNumber = 1001*1001
numbers = []
for i in range(1,lastNumber+1,2):
    numbers.append(i)

n=0
count=0
y=0
result = 0

loop= True

while loop:
    for i in numbers:
        if count < 4:
            try:
                count = count +1
                n = n + 1 + y
                result = result + numbers[n]
            except: 
                loop = False
                break
        else:
            count = 0
            y = y + 1

print (result +1)