import sys
import math

LOCAL = True

if LOCAL:
    input = open('in.txt', 'r')
    output = open('out.txt', 'w')
else:
    input = sys.stdin
    output = sys.stdout

def gcd(a, b):
    while b != 0:
        r = a % b
        a = b
        b = r
    return a

def lcm(a, b):
    return a * b / gcd(a, b)

line = input.readline().strip().split(' ')
A = int(line[0])
B = int(line[1])

ans = -1
min = 10 ** 18 + 1
for N in range(10 ** 5):
    crt = lcm(A + N, B + N)
    if crt < min:
        min = crt
        ans = N

output.write('{}\n'.format(ans))

input.close()
output.close()