#include <bits/stdc++.h>
using namespace std;
template <typename T>
void maxtt(T& t1, T t2) {
  t1 = max(t1, t2);
}
template <typename T>
void mintt(T& t1, T t2) {
  t1 = min(t1, t2);
}
bool debug = 0;
int n, m, k;
int dx[4] = {0, 1, 0, -1}, dy[4] = {1, 0, -1, 0};
string direc = "URDL";
long long ln, lk, lm;
void etp(bool f = 0) {
  puts(f ? "YES" : "NO");
  exit(0);
}
void addmod(int& x, int y, int mod = 1000000007) {
  assert(y >= 0);
  x += y;
  if (x >= mod) x -= mod;
  assert(x >= 0 && x < mod);
}
void et(int x = -1) {
  printf("%d\n", x);
  exit(0);
}
long long fastPow(long long x, long long y, int mod = 1000000007) {
  long long ans = 1;
  while (y > 0) {
    if (y & 1) ans = (x * ans) % mod;
    x = x * x % mod;
    y >>= 1;
  }
  return ans;
}
long long gcd1(long long x, long long y) { return y ? gcd1(y, x % y) : x; }
int a, b, ak;
long long ans = (1LL << 60);
void cal(int g) {
  int x = a / g * g;
  if (x < a) x += g;
  int k = x - a;
  int gg = gcd1(a + k, b + k);
  long long tmp = (long long)(a + k) * (b + k) / gg;
  if (tmp < ans) {
    ans = tmp;
    ak = k;
  }
}
void fmain(int tid) {
  cin >> a >> b;
  if (a == b) {
    puts("0");
    return;
  }
  if (a > b) swap(a, b);
  int c = b - a;
  for (int i = 1; (long long)i * i <= c; i++)
    if (c % i == 0) {
      cal(i);
      cal(c / i);
    }
  printf("%d\n", ak);
}
int main() {
  int t = 1;
  for (int(i) = 1; (i) <= (int)(t); (i)++) {
    fmain(i);
  }
  return 0;
}
