#!/usr/bin/env python3

import array


NO_SOLUTION = -1


def solve(n, m):
    fibs = array.array("Q", (1, 1))
    for _ in range(2, n):
        fibs.append(fibs[-1] + fibs[-2])
    d = fibs[n - 1] - m
    answer = 0
    for i in range(n - 2)[::-1]:
        if d >= fibs[i]:
            d -= fibs[i]
            answer += 1
    return answer if d == 0 else NO_SOLUTION


def main():
    print(solve(*map(int, input().split())))


if __name__ == '__main__':
    main()