#include <iostream>

using namespace std;

long cmmdc(long a, long b){
    while (a!=b){
        if (a>b)
            a = a-b;
        else
            b = b-a;
    }
    return a;
    }

int main()
{
    long a,b,minim,n,aux,bux,i;
    cin >> a >> b;
    i = 0;
    minim =(a*b) / cmmdc(a,b);
    aux = a;
    bux = b;
    do
    {
        i++;
        aux = a+i;
        bux = b+i;
        n = aux*bux / cmmdc(aux,bux);

    }while (n>minim);
    cout << i;
    return 0;
}