import sys
#짧은 기어를 긴 기어의 끝에 닿을 때까지 한 칸씩 밀면서 맞물리는지 봐야함
#반대의 경우도 해봐야 하는데;;
#최장 길이는 두 기어의 길이 합보다 커질 수 없다.
#맞물린다: 이(2)끼리 붙이치지 않으며, 하나라도 홈(1)과 이(2)가 만나야 한다.
a = sys.stdin.readline().rstrip()
b = sys.stdin.readline().rstrip()
def match(short, long):
min_len = len(short) + len(long)
for li in range(len(long)):
ee = False #이끼리 맞물리는가
tooth = False #딱 맞물리는가
for i in range(len(short)):
if li + i >= len(long):
break
s = int(short[i])
l = int(long[li + i])
if s + l == 4:
ee = True
break
if s + l == 3:
tooth = True
if tooth and not ee:
end_point = max(len(long), li + len(short))
min_len = min(min_len, end_point)
return min_len
ans1 = match(a, b)
ans2 = match(b, a)
print(min(ans1, ans2))
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