n = read_line.to_i64
e = read_line.to_i
if e == 0
  puts 0
  exit
end
if n < 0
  n %= 5 ** e
  n += 5 ** e
end
ab = n.abs
a = Array.new(e + 1) do
  v = ab % 5
  ab //= 5
  n < 0 ? (5 - v) % 5 : v
end
if a[0] == 2 || a[0] == 3
  puts "NaN"
  exit
end
if a[0] == 0
  q = [[0, 0]]
elsif a[0] == 1
  q = [[1, 0], [4, 3]]
else
  q = [[2, 0], [3, 1]]
end
1.upto(e - 1) do |i|
  nq = [] of Array(Int32)
  q.each do |cand|
    sum = cand[i]
    1.upto(i - 1) do |j|
      sum += cand[j] * cand[i - j]
    end
    5.times do |j|
      if (j * cand[0] * 2 + sum) % 5 == a[i]
        carry = (j * cand[0] * 2 + sum) // 5
        nc = cand.dup
        nc[i] = j
        nc << carry
        nq << nc
      end
    end
  end
  if nq.empty?
    puts "NaN"
    exit
  end
  q = nq
end
q.each do |cand|
  ans = 0i64
  base = 1i64
  e.times do |i|
    ans += base * cand[i]
    base *= 5
  end
  while ans > 1 << 29
    ans -= 5 ** e
  end
  if ans < -(1 << 29)
    next
  end
  v = ans * ans - n
  c = 0
  while v != 0 && v % 5 == 0
    v //= 5
    c += 1
  end
  if v != 0 && c < e
    puts q.size
    puts q[0]
    puts ans
    puts c
    puts "invalid"
    while true
    end
  end
  puts ans
  exit
end
puts "NaN"