#include <bits/stdc++.h>
using namespace std;

int main() {
    int q;
    cin >> q;
    vector<deque<int>> deques; 
    for (int i = 0; i < q; ++i) {
        string operation;
        int a, x;
        cin >> operation >> a;
        if (a > deques.size()) {
            deques.resize(a);  
        }

        if (operation == "push_back") {
            cin >> x;
            deques[a - 1].push_back(x);
        } else if (operation == "pop_back") {
            if (!deques[a - 1].empty()) {
                deques[a - 1].pop_back();
            }
        } else if (operation == "push_front") {
            cin >> x;
            deques[a - 1].push_front(x);
        } else if (operation == "pop_front") {
            if (!deques[a - 1].empty()) {
                deques[a - 1].pop_front();
            }
        } else if (operation == "size") {
            cout << deques[a - 1].size() << endl;
        } else if (operation == "front") {
            if (!deques[a - 1].empty()) {
                cout << deques[a - 1].front() << endl;
            }
        } else if (operation == "back") {
            if (!deques[a - 1].empty()) {
                cout << deques[a - 1].back() << endl;
            }
        }
    }

    return 0;
}

会超时这个代码