#include "bits/stdc++.h"
using namespace std;
#define ll long long int
#define rep(i,n) for( int i = 0; i < n; i++ )
#define rrep(i,n) for( int i = n; i >= 0; i-- )
#define REP(i,s,t) for( int i = s; i <= t; i++ )
#define RREP(i,s,t) for( int i = s; i >= t; i-- )
#define dump(x)  cerr << #x << " = " << (x) << endl;
#define INF 2000000000
#define mod 1000000007
#define INF2 1000000000000000000
#define int long long

int fib[81];

signed main(void)
{
    cin.tie(0);
    ios::sync_with_stdio(false);
	int N, M;
	cin >> N >> M;
	fib[1] = 1;
	fib[2] = 1;
	REP(i, 3, 80) {
		fib[i] = fib[i - 1] + fib[i - 2];
	}
	if (fib[N] == M) {
		cout << 0 << endl;
		return 0;
	}
	int j = N;
	int tmp = 0;
	int cnt = 0;
	while (j >= 0 && tmp < fib[N] - M) {
		//cout << tmp << " " << cnt << endl;
		while (tmp + fib[j] <= fib[N] - M) {
			tmp += fib[j];
			cnt++;
		}
		if (tmp == M - fib[N]) break;
		j--;
	}
	if (j >= 0 && fib[N] >= M) {
		cout << cnt << endl;
	}
	else {
		cout << -1 << endl;
	}



    return 0;
}