#include <iostream>
using namespace std;

typedef long long ll;

ll fibo[100];

int main() {
    int N;
    ll M;
    cin >> N >> M;

    fibo[1] = 1;
    for (int i = 2; i <= N; i++) {
        fibo[i] = fibo[i - 1] + fibo[i - 2];
    }

    int ans = 0;
    ll diff = fibo[N] - M;
    for (int i = N - 2; i >= 1; i--) {
        if (diff >= fibo[i]) {
            diff -= fibo[i];
            ans++;
        }
    }
    if (diff == 0) cout << ans << endl;
    else cout << -1 << endl;

    return 0;
}