import sys
from pprint import pprint
from functools import reduce

maps = []

with open(sys.argv[1]) as file:
    for line in file:
        maps.append([int(x) for x in line.rstrip().split(' ')])

def calc(line):
    diff = []
    for i in range(0,len(line)-1):
        diff.append(line[i+1]-line[i])
    if not all(v == 0 for v in diff):
        last.append(diff[-1])
        calc(diff)
    return 0
result = [] 
for mdx,m in enumerate(maps):
    last = []
    last.append(m[-1])
    last.append(calc(m))
    result.append(reduce(lambda x, y: x+y, last))

print(sum(result))