// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

contract DataStorage {
    mapping(address => string) public storedData;
    mapping(string => bool) private dataExists;

    event DataStored(address indexed _from, string _data);

    function setData(string memory _data) public {
        require(bytes(_data).length <= 9, "Data length exceeds 9 characters");
        require(!dataExists[_data], "Data already exists");

        storedData[msg.sender] = _data;
        dataExists[_data] = true;

        emit DataStored(msg.sender, _data);
    }

    function getData(address _address) public view returns (string memory) {
        return storedData[_address];
    }
}