#include <iostream>
#include <string>

using namespace std;

int main() {
    string word="Good";

    word.replace(0,1,"F");

    cout << word << endl;

    //Using array notation.
    word[0]='M';

    cout << word << endl;

    word.erase(3,1);

    cout << word << endl;

    word.insert(0,"S");

    //word.insert(word.length(),"TH");
    word.append("TH");

    cout << word << endl;

}