#include <bits/stdc++.h>

using namespace std;

int main()
{
    deque<string> d1(5, "disen");
    d1.push_front("jack");
    d1.push_back("mack");
    d1.insert(d1.begin() + 1, "lucy");
    cout << "first element is: " << d1.front() << endl;
    cout << "last element is: " << d1.back() << endl;

    deque<string>::iterator it = d1.begin();
    cout << "second element is: " << *(it + 1) << endl;

    return 0;
}