fibonacci_list = { 1=>1, 2=>1 }
(3..80).each{|n|
	fibonacci_list[n] = fibonacci_list[n-1] + fibonacci_list[n-2]
}

n, m = gets.split.map(&:to_i)

diff = fibonacci_list[n] - m
count = 0
3.upto(n){|i|
	if diff >= fibonacci_list[n-i+1]
		diff -= fibonacci_list[n-i+1]
		count += 1
	end
}
puts diff == 0 ? count : -1