contract Token is SafeMath {
     // Functions:
     /// @return total amount of tokens
     function totalSupply()public  constant returns (uint256 supply);

     /// @param _owner The address from which the balance will be retrieved
     /// @return The balance
     function balanceOf(address _owner)public constant returns (uint256 balance);

     /// @notice send `_value` token to `_to` from `msg.sender`
     /// @param _to The address of the recipient
     /// @param _value The amount of token to be transferred
     function transfer(address _to, uint256 _value)public returns(bool);

     /// @notice send `_value` token to `_to` from `_from` on the condition it is approved by `_from`
     /// @param _from The address of the sender
     /// @param _to The address of the recipient
     /// @param _value The amount of token to be transferred
     /// @return Whether the transfer was successful or not
     function transferFrom(address _from, address _to, uint256 _value)public returns(bool);

     /// @notice `msg.sender` approves `_addr` to spend `_value` tokens
     /// @param _spender The address of the account able to transfer the tokens
     /// @param _value The amount of wei to be approved for transfer
     /// @return Whether the approval was successful or not
     function approve(address _spender, uint256 _value)public returns (bool success);

     /// @param _owner The address of the account owning tokens
     /// @param _spender The address of the account able to transfer the tokens
     /// @return Amount of remaining tokens allowed to spent
     function allowance(address _owner, address _spender)public constant returns (uint256 remaining);

     // Events:
     event Transfer(address indexed _from, address indexed _to, uint256 _value);
     event Approval(address indexed _owner, address indexed _spender, uint256 _value);
}
// Standard token interface (ERC 20)
// https://github.com/ethereum/EIPs/issues/20
function approve(address _spender, uint256 _value)public returns (bool success);

/// @notice `msg.sender` approves `_addr` to spend `_value` tokens
/// @param _spender The address of the account able to transfer the tokens
/// @param _value The amount of wei to be approved for transfer
/// @return Whether the approval was successful or not