import sys
W,H = 1000,1000
grid = [ [ 0 for _ in range(W) ] for _ in range(H) ]
L = eval(sys.stdin.read())
sign = lambda x: (1, -1)[x<0]
n=0
def incr(x,y):
	global n
	grid[x][y]+=1
	if grid[x][y]==2:
		n+=1
for ((x1,y1),(x2,y2)) in L:
	if x1 == x2:
		for y in range(min(y1,y2), max(y1,y2)+1):
			incr(x1,y)
	elif y1 == y2:
		for x in range(min(x1,x2), max(x1,x2)+1):
			incr(x,y1)
	else:
		r = abs(x1-x2)
		i = sign(x2-x1)
		j = sign(y2-y1)
		for a in range(r+1):
			incr(x1+a*i,y1+a*j)
print(n)