#include <bits/stdc++.h>
using namespace std;
using i64 = int64_t;
i64 f[100];
int main() {
    f[1] = f[2] = 1;  // 题面如此(
    for (int i = 3; i < 81; i++) f[i] = f[i - 1] + f[i - 2];
    i64 n, m;
    cin >> n >> m;
    i64 diff = f[n] - m;
    int ans = 0;
    for (int i = n - 2; i > 0; i--)
        if (diff >= f[i])
            diff -= f[i],  // i influnce = Fib[i]
                ans++;
    if (diff == 0)
        cout << ans << endl;
    else
        cout << -1 << endl;
    return 0;
}