#include <iostream>
#include <unordered_map>
using namespace std;
typedef long long int64;
int64 fib[80 + 1] = {0, 1, 1};
int64 n, m;
int solve(int i, int64 k, int d)
{
    while(i >= 1 && k - fib[i] < m)
        i--;
    if(i < 1)
        return -1;
    if(k - fib[i] == m)
        return d + 1;
    return solve(i - 1, k - fib[i], d + 1);
}
int main(void)
{
    cin >> n >> m;
    for(int i = 3; i <= n; i++)
        fib[i] = fib[i - 1] + fib[i - 2];
    if(fib[n] == m)
    {
        cout << 0 << endl;
        return 0;
    }
    cout << solve(n - 2, fib[n], 0) << endl;
    return 0;
}