#include <sstream>
#include <string>
#include <vector>
#include <map>
#include <algorithm>
#include <iostream>
#include <utility>
#include <set>
#include <cctype>
#include <queue>
#include <stack>
#include <cstdio>
#include <cstdlib>
#include <cmath>

#define INF 1000000000

using namespace std;
typedef long long ll;

int main(void) {
    ll M, N;
    cin >> M >> N;
    ll g = __gcd(M, N);
    M /= g;
    N /= g;
    ll num = 0;
    while (1) {
        if (M == N) {
            if (M == 1) break;
            cout << -1 << endl;
            return 0;
        }
        if (M > N) {
            ll k = M/N;
            if (k != 1) {
                M -= (k-1)*N;
                num += k-1;
            }
            else {
                M -= N;
                num++;
            }
        } else {
            swap(M, N);
            num++;
        }
    }
    cout << num << endl;
    return 0;
}