#!/usr/bin/python
 
# Project Euler - Problem 11
 
print "\nProject Euler - Problem 11"
print "In a 20x20 grid, find the greatest"
print "product of 4 adjacent numbers."
 
f = open("problem11.grid",'r')
x = []
ans = 0
beef = True
# Load data into 20x20 list
for m in xrange(20):
    x.append([])
    for n in xrange(20):
        x[m].append(int(f.read(3)))
 
for m in xrange(16):
    for n in xrange(16):
        prod=[]
        # Multiply Rows
        prod.append(x[m][n] * x[m][n+1] * x[m][n+2] * x[m][n+3])
        prod.append(x[m+1][n] * x[m+1][n+1] * x[m+1][n+2] * x[m+1][n+3])
        prod.append(x[m+2][n] * x[m+2][n+1] * x[m+2][n+2] * x[m+2][n+3])
        prod.append(x[m+3][n] * x[m+3][n+1] * x[m+3][n+2] * x[m+3][n+3])
        # Multiply Columns
        prod.append(x[m][n] * x[m+1][n] * x[m+2][n] * x[m+3][n])
        prod.append(x[m][n+1] * x[m+1][n+1] * x[m+2][n+1] * x[m+3][n+1])
        prod.append(x[m][n+2] * x[m+1][n+2] * x[m+2][n+2] * x[m+3][n+2])
        prod.append(x[m][n+3] * x[m+1][n+3] * x[m+2][n+3] * x[m+3][n+3])
        # Diagonals
        prod.append(x[m][n] * x[m+1][n+1] * x[m+2][n+2] * x[m+3][n+3])
        prod.append(x[m+3][n] * x[m+2][n+1] * x[m+1][n+2] * x[m][n+3])
        if max(prod) > ans:
            ans = max(prod)
 
print ans