bridge

#include<bits/stdc++.h>
#define ll long long
using namespace std;

ll gcd(ll a, ll b)
{
    if (a == 0)
        return b;
    return gcd(b%a, a);
}

ll commDiv(ll a,ll b)
{
    ll n = gcd(a, b);

    ll result = 0;
    for (ll i=1; i*i<=n; i++)
    {
        if (n%i==0)
        {
            if (n/i == i)
                result += 1;
            else
                result += 2;
        }
    }
    return result;
}

int main()
{
    ll s, f ;
    while(scanf("%lld %lld",&s,&f)!=EOF)
    {
        if(s > f) swap(s,f) ;

        ll p ;
        p = commDiv(s, f) ;

        if(p == 1)
        {
            cout << "-1" << endl ;
        }
        else
        {
            cout << (p-1) << endl ;
        }

    }
    return 0;
}