'''
In the 20×20 grid below, four numbers along a diagonal line have been marked in red.

(xd)

The product of these numbers is 26 × 63 × 78 × 14 = 1788696.

What is the greatest product of four adjacent numbers in the same direction (up, down, left, right, or diagonally) in the 20×20 grid?
'''
grid = [
[ 8, 2,22,97,38,15, 0,40, 0,75, 4, 5, 7,78,52,12,50,77,91, 8],
[49,49,99,40,17,81,18,57,60,87,17,40,98,43,69,48, 4,56,62, 0],
[81,49,31,73,55,79,14,29,93,71,40,67,53,88,30, 3,49,13,36,65],
[52,70,95,23, 4,60,11,42,69,24,68,56, 1,32,56,71,37, 2,36,91],
[22,31,16,71,51,67,63,89,41,92,36,54,22,40,40,28,66,33,13,80],
[24,47,32,60,99, 3,45, 2,44,75,33,53,78,36,84,20,35,17,12,50],
[32,98,81,28,64,23,67,10,26,38,40,67,59,54,70,66,18,38,64,70],
[67,26,20,68, 2,62,12,20,95,63,94,39,63, 8,40,91,66,49,94,21],
[24,55,58, 5,66,73,99,26,97,17,78,78,96,83,14,88,34,89,63,72],
[21,36,23, 9,75, 0,76,44,20,45,35,14, 0,61,33,97,34,31,33,95],
[78,17,53,28,22,75,31,67,15,94, 3,80, 4,62,16,14, 9,53,56,92],
[16,39, 5,42,96,35,31,47,55,58,88,24, 0,17,54,24,36,29,85,57],
[86,56, 0,48,35,71,89, 7, 5,44,44,37,44,60,21,58,51,54,17,58],
[19,80,81,68, 5,94,47,69,28,73,92,13,86,52,17,77, 4,89,55,40],
[ 4,52, 8,83,97,35,99,16, 7,97,57,32,16,26,26,79,33,27,98,66],
[88,36,68,87,57,62,20,72, 3,46,33,67,46,55,12,32,63,93,53,69],
[ 4,42,16,73,38,25,39,11,24,94,72,18, 8,46,29,32,40,62,76,36],
[20,69,36,41,72,30,23,88,34,62,99,69,82,67,59,85,74, 4,36,16],
[20,73,35,29,78,31,90, 1,74,31,49,71,48,86,81,16,23,57, 5,54],
[ 1,70,54,71,83,51,54,69,16,92,33,48,61,43,52, 1,89,19,67,48]]

def prod(ints):
	ans = 1
	for num in ints:
		ans = ans * num
	return ans


the_product = 0

for x in grid: #left-right
	for y in range(0, len(x)-5):
		product = 1
		for num in x[y:y+4]:
			product = product * num
		if product > the_product:
			the_product = product

for i in range(0, len(grid)-1): #up-down
	for j in range(0, len(grid[i])-5):
		product = 1
		for x in range(0,4):
			product = product * grid[j+x][i]
		if product > the_product:
			the_product = product

for i in range(0, len(grid)-5): #topleft-bottomright
	for j in range(0, len(grid[i])-5):
		product = 1
		for x in range(0,4):
			product = product * grid[i+x][j+x]
		if product > the_product:
			the_product = product

for i in range(0, len(grid)-5): #topright-bottomleft
	for j in range(3, len(grid[i])-1):
		product = 1
		for x in range(0,4):
			product = product * grid[i+x][j-x]
		if product > the_product:
			the_product = product

print(the_product)