#include<bits/stdc++.h>
using namespace std;
#define endl "\n"
deque <int> q[300000];
string s;
int n;
int main(){
	cin>>n;
	for(int i = 1,a,b;i <= n;i++){
		cin >> s;
		if(s == "push_back"){
			cin >> a >> b;
			q[a].push_back(b);
		}else if(s == "pop_back"){
			cin >> a;
			if(!q[a].empty()){
				q[a].pop_back();
			}else{
				continue;
			}
		}else if(s == "push_front"){
			cin >> a >> b;
			q[a].push_front(b);
		}else if(s == "pop_front"){
			cin >> a;
			if(!q[a].empty()){
				q[a].pop_front();
			}else{
				continue;
			}
		}else if(s == "size"){
			cin >> a;
			cout << q[a].size() << endl;
		}else if(s == "front"){
			cin >> a;
			if(!q[a].empty()){
				cout << q[a].front() << endl;
			}else{
				continue;
			}
		}else if(s == "back"){
			cin >> a;
			if(!q[a].empty()){
				cout << q[a].back() << endl;
			}else{
				continue;
			}
		}
	}
	return 0;
}

$\color{purple}{\text{RE}}$ on #$19$