#include <iostream>
#define sizeh 1000

using namespace std;

int* deque;
int dh = 500, dt = 500, sum = 0;;

void push_front( int x)
{
    if (dh < 1) dh += sizeh;
    deque[(--dh) % sizeh] = x;
    sum++;
}

void push_back( int x)
{
    deque[(dt++) % sizeh] = x;
    sum++;
}

int pop_front()
{
    sum--;
    return deque[(dh++) % sizeh];
}

int pop_back()
{
    sum--;
    if (dt < 1) dt += sizeh;
    return deque[(--dt) % sizeh];
}

void del_deque() {
    dt = 500;
    dh = 500;
    sum = 0;
}

int main() {
    int a = 0,  b = 0;
    deque = new int[sizeh];
    while(cin >> a){
        if (a == 1) {
            cin >> b;
            push_front(b);
        }
        else if (a == 2) {
            cin >> b;
            push_back(b);
        }
        else if (a == 3) {
            cout << pop_front();
        }
        else if (a == 4) {
            cout << pop_back();
        }
        else if (a == 5) {

        }
        else if (a == 6) {

        }
        else if (a == 7) {
            cout << sum;
        }
        else if (a == 8) {
            del_deque();
        }
        else if (a == 9) {
            return 0;
        }
    }
    delete[] deque;
    return 0;
}