#include <iostream>
#include <numeric>
using namespace std;
long gcd(long a, long b)
{
    for (;;)
    {
        if (a == 0) return b;
        b %= a;
        if (b == 0) return a;
        a %= b;
    }
}

long lcm(long a, long b)
{
    long temp = gcd(a, b);

    return temp ? (a / temp * b) : 0;
}
int main()
{
int a,b;
cin>>a>>b;
long mn= lcm(a,b),n=0;
for(long i = 1; i<=a*b;i++)
{
long x= lcm(a+i,b+i);
if(x<mn)
mn=x,n=i;
}
cout<<n;
}