#! ruby
# yukicoder My Practice
# author: Leonardone @ NEETSDKASU

def gs(); gets.chomp; end
def gi(); gets.to_i; end
def gss(); gets.chomp.split; end
def gis(); gss.map(&:to_i); end

N, M = gis

def rec(xs,i,d,p)
    return p if d == 0
    return -1 if i >= xs.size
    x, s = xs[i]
    return -1 if s < d
    return rec(xs,i+1,d,p) if x > d
    r1 = rec(xs,i+1,d,p)
    r2 = rec(xs,i+1,d-x,p+1)
    return r2 if r1 < 0
    return r1 if r2 < 0
    [r1, r2].min
end

def fibs(n)
    f = [1, 1]
    (2...n).each do |i|
        f << f[i - 1] + f[i - 2]
    end
    fs = [[1,1]]
    (1...f.size).each do |i|
        fs << [f[i], f[i] + fs[i-1][1]]
    end
    fs.reverse
end

def solve(n,m)
    f = fibs(n)
    rec(f[2..-1], 0, f[0][0] - m, 0)
end

p solve(N,M)