#include <iostream>
#include <string>
#include <regex>

std::string unescapeUnicode(const std::string& input) {
    // Regular expression pattern to match Unicode escape sequences
    std::regex pattern("\\\\u([0-9A-Fa-f]{4})");

    // Function to replace each Unicode escape sequence with its corresponding character
    auto replaceUnicode = [&](const std::smatch& match) -> std::string {
        int codepoint = std::stoi(match[1].str(), nullptr, 16);
        return std::string(1, static_cast<char>(codepoint));
    };

    // Use std::regex_replace to replace all occurrences of Unicode escape sequences
    return std::regex_replace(input, pattern, replaceUnicode);
}