1
#include<bits/stdc++.h>
2
using namespace std;
3
const int M=1e6+10;
4
deque<int>dq[M];
5
int main()
6
{
7
    int q;
8
    cin>>q;
9
    while(q--)
10
    {
11
        string op;
12
        cin>>op;
13
        if(op=="push_back")
14
        {
15
            int a,x;
16
            cin>>a>>x;
17
            dq[a].push_back(x);
18
        }
19
        else if(op=="pop_back")
20
        {
21
            int a;
22
            cin>>a;
23
            if(!dq[a].empty())
24
            {
25
                dq[a].pop_back();
26
            }
27
        }
28
        else if(op=="push_front")
29
        {
30
            int a,x;
31
            cin>>a>>x;
32
            dq[a].push_front(x);
33
        }
34
        else if(op=="pop_front")
35
        {
36
            int a;
37
            cin>>a;
38
            if(!dq[a].empty())
39
            {
40
                dq[a].pop_front();
41
            }
42
        }
43
        else if(op=="size")
44
        {
45
            int a;
46
            cin>>a;
47
            cout<<dq[a].size()<<endl;
48
        }
49
        else if(op=="front")
50
        {
51
            int a;
52
            cin>>a;
53
            if(!dq[a].empty())
54
            {
55
                cout<<dq[a].front()<<endl;
56
            }
57
        }
58
        else if(op=="back")
59
        {
60
            int a;
61
            cin>>a;
62
            if(!dq[a].empty())
63
            {
64
                cout<<dq[a].back()<<endl;
65
            }
66
        }
67
    }
68
    return 0;
69
}