#include <iostream>

using namespace std;

int main ()
{
    int a,b,aux,oc,i;
    cin>>a>>b;
    if (b>a)
    {
        aux=a;
        a=b;
        b=aux;
    }
    oc=0;
    i=1;
    while (oc==0)
    {
        if ((a+i)%(b+i)==0)
            oc=1;
        else
            i++;
    }
    cout<<i;
}