import sys
input = lambda:sys.stdin.readline().strip()

def sub(a, b):
    # a - b
    
    l = len(a)
    ans = [0 for _ in range(l)]

    for i in range(l-1, -1, -1):
        if a[i] >= b[i]:
            ans[i] = a[i] - b[i]
        else:
            ans[i] = a[i] - b[i] + 10
            a[i-1] -= 1
    
    return ans

def solve(a, b):
    # a + x | b - x

    l = len(a)
    idx = 0

    for i in range(l-1, -1, -1):
        if a[i] + b[i] >= 10:
            idx = i - 1
    
    while idx >= 0 and a[i] + b[i] == 9:
        idx -= 1
    
    res = [0 for _ in range(l)]
    for i in range(idx):
        res[i] = a[i]
    res[idx] = a[idx] + 1
    for i in range(idx+1, l):
        res[i] = 0

    # print(res)
    # print(a)
    # print()

    
    return sub(res, a)

a = [*map(int, [*input()])]
b = [*map(int, [*input()])]

la = len(a)
lb = len(b)

l = max(len(a), len(b)) + 1
a = [0 for _ in range(l-la)] + a
b = [0 for _ in range(l-lb)] + b

# print(a)
# print(b)

ans1 = solve(a, b)
ans2 = solve(b, a)

# print(ans1)
# print(ans2)

res = ans1

for i in range(l):
    if ans1[i] == ans2[i]:
        continue
    if ans1[i] < ans2[i]:
        res = ans1
        break
    else:
        res = ans2
        break

res = res[::-1]
while len(res) and res[-1] == 0:
    res.pop()
if len(res) == 0:
    res.append(0)
res = res[::-1]

print(*res, sep='')