DeclarationError: Identifier not found or not unique - solidity

Question

I'm trying to compile my sol file, but it's giving me this error. Why am I getting this error?
DeclarationError: Identifier not found or not unique. -->
project:/contracts/MemoTokenSale.sol:11:5: | 11 | MemoToken
public token; | ^^^^^^^^^
Compilation failed. See above. Truffle v5.4.23 (core: 5.4.23) Node
v16.13.0
The following is my code
// SPX-License-Identifier: MIT
pragma solidity ^0.8.0;
import './MemoToken.sol';
import "#chainlink/contracts/src/v0.8/interfaces/AggregatorV3Interface.sol";
contract MemoTokenSale {
address payable public admin;
address payable private ethFunds = payable(0x15b22B37679eF92672dA117F4357e048319008AD); // Web3 Account
MemoToken public token;
uint256 public tokensSold;
int public tokenPriceUSD;
AggregatorV3Interface internal priceFeed;
uint256 public transactionCount;
event Sell(address _buyer, uint256 _amount);
struct Transaction {
address buyer;
uint256 amount;
}
mapping(uint256 => Transaction) public transaction;
constructor(MemoToken _token) {
priceFeed = AggregatorV3Interface(0x9326BFA02ADD2366b30bacB125260Af641031331); // ChainLink Contracts
tokenPriceUSD = 50;
token = _token;
admin = payable(msg.sender);
}
function getETHPrice() public view returns(int) {
(, int price, , , ) = priceFeed.latestRoundData();
return (price / 10^8);
}
function memoTokenPriceInETH() public view returns(int) {
int ethPrice = getETHPrice();
return tokenPriceUSD / ethPrice;
}
function buyToken(uint256 _amount) public payable {
int memoTokenPriceETH = memoTokenPriceInETH();
// Check that the buyer sends the enough ETH
require(int(msg.value) >= memoTokenPriceETH * int(_amount));
// Check that the sale contract provides the enough ETH to make this transaction.
require(token.balanceOf(address(this)) >= _amount);
// Make the transaction inside of the require
// transfer returns a boolean value.
require(token.transfer(msg.sender, _amount));
// Transfer the ETH of the buyer to us
ethFunds.transfer(msg.value);
// Increase the amount of tokens sold
tokensSold += _amount;
// Increase the amount of transactions
transaction[transactionCount] = Transaction(msg.sender, _amount);
transactionCount++;
// Emit the Sell event
emit Sell(msg.sender, _amount);
}
function endSale() public {
require(msg.sender == admin);
// Return the tokens that were left inside of the sale contract
uint256 amount = token.balanceOf(address(this));
require(token.transfer(admin, amount));
selfdestruct(payable(admin));
}
}