#include <bits/stdc++.h>

#define pb push_back
#define mp make_pair
#define mt make_tuple
#define ll long long
#define pii pair<int,int>
#define tii tuple <int,int,int>
#define N 200005
#define mod 1000000005
#define X first
#define Y second
#define eps 0.0000000001
#define all(x) x.begin(),x.end()
#define tot(x) x+1,x+n+1
using namespace std;


ll a, b, i, x, mx, sol;
int main() {
    cin.sync_with_stdio(false);
    cout.sync_with_stdio(false);
    cin >> a >> b;
    mx = a * b / __gcd(a, b);

    for(i = 1; i <= 30000000; i++) {
        a++;
        b++;
        x = a * b / __gcd(a, b);

        if(x < mx) {
            mx = x;
            sol = i;
        }
    }

    cout << sol;
    return 0;
}