local n, k = io.read("*n", "*n")
if n == 1 then
  print(1)
  os.exit()
elseif n == 2 then
  print(k == 1 and 01 or 11)
  os.exit()
end
if k == 1 then
  print(-1)
  os.exit()
end
if n <= 4 then
  print(string.rep("1", k) .. string.rep("0", n - k))
  os.exit()
end
if k == 2 then
  print(-1)
  os.exit()
end
if n <= 6 then
  print(string.rep("1", k) .. string.rep("0", n - k))
  os.exit()
end
if n == 7 then
  if k == 3 then
    print("0001011")
  else
    print(string.rep("1", k) .. string.rep("0", n - k))
  end
  os.exit()
end
if n == 8 then
  if k == 3 then
    print("00010111")
  else
    print(string.rep("1", k) .. string.rep("0", n - k))
  end
  os.exit()
end
if k == 3 then
  print(-1)
  os.exit()
end
io.write(string.rep("1", k))
local rem = n - k
local v = "010011"
local lp = math.floor(rem / 6)
io.write(string.rep(v, lp))
rem = rem % 6
if 0 < rem then
  io.write(v:sub(1, rem))
end
io.write("\n")