0分，求调

#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define endl '\n'
const int N = 1e6+10;
deque<ll> d[N];
int m,q;
int main(){
    ios::sync_with_stdio(0);
    cin.tie(0),cout.tie(0);
    cin>>q;
    while(q--){
        string s;
        int a,b;
        cin>>s;
        if(s=="push_back"){
            cin>>a>>b;
            d[a].push_back(b);
        }
        else if(s=="pop_back"){
            cin>>a;
            if(!d[a].empty()) d[a].pop_back();
        }
        else if(s=="push_front"){
            cin>>a>>b;
            d[a].push_front(b);
        }
        else if(s=="pop_front"){
            cin>>a;
            if(!d[a].empty()) d[a].pop_front();
        }
        else if(s=="size"){
            cin>>a;
            cout<<d[a].size()<<endl;
        }
        else if(s=="front"){
            cin>>a;
            cout<<d[a].front()<<endl;
        }
        else if(s=="back"){
            cin>>a;
            cout<<d[a].back()<<endl;
        }
    }
    return 0;
}