#include <string>
#include <vector>
#include <iostream>

class Letter {
public:
    Letter(std::string from, std::string to); // Constructor
    void add_line(std::string line); // Add a line of text to the body of the letter
    std::string get_text(); // Get the entire text of the letter

private:
    std::string sender;
    std::string recipient;
    std::vector<std::string> body;
};

// Implementation of the constructor and methods
Letter::Letter(std::string from, std::string to) : sender(from), recipient(to) {}

void Letter::add_line(std::string line) {
    body.push_back(line);
}

std::string Letter::get_text() {
    // Concatenate strings correctly
    std::string text = "Dear " + recipient + ":\n\n"; 
    for (const auto& line : body) {
        text += line + "\n";
    }
    text += "\nSincerely,\n\n" + sender;
    return text;
}

int main() {
    Letter letter("Mary", "John");
    letter.add_line("I am sorry we must part.");
    letter.add_line("I wish you all the best.");
    std::cout << letter.get_text() << std::endl;
    return 0;
}