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

#include <iostream>
using namespace std;
int main ()
{
    int a;
    int * ptr_b;
    int ** ptr_c;
    a = 1;
    ptr_b = &a;
    ptr_c = &ptr_b;
    cout << a << "\n";
    cout << *ptr_b << "\n";
    cout << *ptr_c << "\n";
    cout << **ptr_c << "\n";
    return 0;
}