D = gets.to_i
H = 3.times.map { gets.to_i }

if D == 0
  if H[0] < H[1] && H[1] > H[2] && H.size == H.uniq.size
    puts 0
  elsif H[0] > H[1] && H[1] < H[2] && H.size == H.uniq.size
    puts 0
  else
    puts -1
  end

  exit
end

def f(h)
  cnt = 0

  if h[0] == h[2]
    h[0] = [0, h[0] - D].max
    cnt += 1
  end

  if h[0] == h[2]
    return Float::INFINITY
  end

  if h[0] <= h[1]
    diff = h[1] - h[0] + 1
    c = Rational(diff, D).ceil
    cnt += c
    h[1] = [0, h[1] - c * D].max
  end

  if h[2] <= h[1]
    diff = h[2] - h[0] + 1
    c = Rational(diff, D).ceil
    cnt += c
    h[2] = [0, h[2] - c * D].max
  end

  if h[0] == h[1]
    return Float::INFINITY
  end

  if h[1] == h[2]
    return Float::INFINITY
  end

  cnt
end

def g(h)
  cnt = 0

  if h[0] >= h[1]
    diff = h[0] - h[1] + 1
    c = Rational(diff, D).ceil
    cnt += c
    h[0] = [0, h[1] - c * D].max
  end

  if h[2] >= h[1]
    diff = h[2] - h[1] + 1
    c = Rational(diff, D).ceil
    cnt += c
    h[2] = [0, h[2] - c * D].max
  end

  if h[0] == h[2]
    h[0] = [0, h[0] - D].max
    cnt += 1
  end

  if h[0] == h[2]
    return Float::INFINITY
  end

  cnt
end

a1 = f(H.dup)
a2 = g(H.dup)
ans = [a1, a2].min

if ans == Float::INFINITY
  puts -1
else
  puts ans
end