import sys
input = sys.stdin.readline

def linput(tt=int):
	return list(map(tt,input().split()))

def main():
	H,W = linput()
	sr,sc = linput()
	gr,gc = linput()
	
	res = abs(gc-sc) + abs(gr-sr)
	print(res)

if __name__ == "__main__":
	main()