Created using remix-ide: Realtime Ethereum Contract Compiler and Runtime. Load this file by pasting this gists URL or ID at https://remix.ethereum.org/#version=soljson-v0.8.4+commit.c7e474f2.js&optimize=true&runs=200&gist=

contracts...test_video.sol

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.4;

import "erc721a/contracts/ERC721A.sol";
import "@openzeppelin/contracts/utils/Strings.sol";
import "@openzeppelin/contracts/access/Ownable.sol";


contract UnitedForUkraine is ERC721A, Ownable {

    string private baseURI = "ipfs://QmPKAqXrWmT1DAp4K3SAKFYPMdkH6QW8LPp21woJ1oCsbY/";

    constructor() ERC721A("UnitedForUkraine", "UnitedForUkraine") {
        _safeMint(msg.sender, 1);
    }

    function tokenURI(uint256 tokenId) public view override returns (string memory) {
        return string(abi.encodePacked(baseURI, Strings.toString(tokenId), ".json"));
    }

    function setNewBaseURI(string memory _newbaseURI) public onlyOwner {
        baseURI = _newbaseURI;                         
    }

    function mintQuantity(uint256 _quantity) public onlyOwner {
        _safeMint(msg.sender, _quantity);
    }
}