What will be the output of the following C++ code?

#include <iostream>
#include <list>
#include <queue>
using namespace std;
int main()
{
    queue<char> q;
    q.push('a');
    q.push('b');
    q.push('c');
    cout << q.front();
    q.pop();
    cout << q.front();
    q.pop();
    cout << q.front();
    q.pop();
}