from collections import deque
#作者堀江、特に賢い解法も思いつかないので平凡なコード
#会津大学オンラインジャッジ問0121Seven Puzzle書きかけ.合格。
 
def f():
	hs={}
	ds=[[1,4],[2,5,0],[3,6,1],[7,2],[5,0],[6,1,4],[7,2,5],[3,6]]
	e=(7,1234567)
	qs=deque([e])
	hs[e[1]]=0
	while len(qs)>0:
		e=qs.popleft()
		i,n=e[0],e[1]
		l=hs[n]+1
		r1=10**i
		for j in ds[i]:
			r2=10**j
			b2=(n//r2)%10
			n2=n+b2*(r1-r2)
			if (n2 in hs)==False:
				hs[n2]=l
				qs.append((j,n2))
	return hs
try:
	hs=f()
	while True:
		n=int("".join(input().split(" ")))
		print(hs[n])
except EOFError:
	next

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MCAxIDIgMyA0IDUgNiA3CjEgMCAyIDMgNCA1IDYgNwo3IDYgNSA0IDMgMiAxIDA=

0 1 2 3 4 5 6 7
1 0 2 3 4 5 6 7
7 6 5 4 3 2 1 0