Receiving a DeclarationError: Identifier not found or not unique while using counters using Remix - solidity

Question

I am trying to run the code which is generating an error stating that DeclarationError: Identifier not found or not unique.
The smart contract NFTCollection is a solidity code which enables me to mint a specific number of ERC721 Tokens and to count the tokens of owner. I am receiving a error while displaying the error message "DeclarationError: Identifier not found or not unique" at line 20 which reads "using Counters for Counters.counter;"
Please find the code below.
Any help would be highly appreciated.
The contract and the error message.
pragma solidity ^0.8.4;
// Importing required libraries
/*
import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/591c12d22de283a297e2b551175ccc914c938391/contracts/token/ERC721/ERC721.sol";
import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/591c12d22de283a297e2b551175ccc914c938391/contracts/access/Ownable.sol";
import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/591c12d22de283a297e2b551175ccc914c938391/contracts/utils/Counters.sol";
import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/591c12d22de283a297e2b551175ccc914c938391/contracts/token/ERC721/extensions/ERC721Enumerable.sol";
*/
import "#openzeppelin/contracts/token/ERC721/ERC721.sol";
import "#openzeppelin/contracts/access/Ownable.sol";
import "#openzeppelin/contracts/utils/Counters.sol";
import "#openzeppelin/contracts/token/ERC721/extensions/ERC721Enumerable.sol";
// This is a simple NFT contract
//Start of a contract
//INitialising contract as a ERC721, ERC721Enumerable, Ownable contract.
contract NFTCollection is ERC721, ERC721Enumerable, Ownable {
using Counters for Counters.counter;
// Specifing the maximum supply
uint256 maxSupply = 1000000;
// Initiatina a counter to store to be able to use Counters on uint265 without impacting the rest of the uint256 in the contract.
//Counter helps to find every function from a single library to a type to reduce gass fee.
Counters.Counter private _tokenIDCounter;
// Initialising a constructor.
constructor(string memory _name, string memory _symbol)
ERC721(_name, _symbol){}
// ERC721 interface is initialised and the _name, _symbol details aere passed in to hold.
//End of constructor.
//Start of function mint.
//This function is used to mint ERC721 tokens.
//Mint function adds the capability to mint ERC721 tokens and assign it to a address which accepts user address, number of tokens as arguments.
function mint(address _user, uint256 _amount) public {
//Start of for loop
for(uint256 i;i<_amount;i++)
{
//Incrementing the _tokenIdCounter by 1 using increment function.
_tokenIdCounter.increment();
// Creating a variable which stores the current value of _tokenIdCounter.
uint256 tokenId = _tokenIdcounter.current();
//Using safemint to mint ERC721 Tokens.
_safeMint(_user,tokenId);
}
}//End of function mint.
//Start of function tokensOfOwner
// This function is used to keep track of the owners Tokens.
// The function seeks a owner address to check the number of tokens he owns.
function tokensOfOwner(address _owner) public view returns (uint256[] memory)
{ // Creating a ownerTokenCount which stores the balance of the owner.
uint256 ownerTokenCount = balanceOf(_owner);
// Creating a memory variable and storing a array of ownerTokenCount.
uint256[] memory ownedTokenIds = new uint256[](ownerTokenCount);
for (uint256 i; i < ownerTokenCount; ++i) {
ownedTokenIds[i] = tokenOfOwnerByIndex(_owner, i);
}//End of for loop
return ownedTokenIds; //Return statement.
}
// Function overrides required by solidity
function _beforeTokenTransfer(
address from,
address to,
uint256 tokenId
) internal override(ERC721, ERC721Enumerable) {
super._beforeTokenTransfer(from, to, tokenId);
}
function supportsInterface(bytes4 interfaceId)
public
view
override(ERC721, ERC721Enumerable)
returns (bool)
{
return super.supportsInterface(interfaceId);
}
}
Error Message
--> contracts/nft.sol:20:24:
|
20 | using Counters for Counters.counter;~~~