#include<bits/stdc++.h>
using namespace std;
list<int>q[1000001];
int main(){
	ios::sync_with_stdio(0);
	cin.tie(0),cout.tie(0);
	int k;
	cin>>k;
	for(int i=1;i<=k;i++){
		string s;
		cin>>s;
		if(s=="push_back"){
			int a,x;
			cin>>a>>x; 
			q[a].push_back(x);
		}
		if(s=="pop_back"){
			int a;
			cin>>a;
			if(q[a].empty())
			continue;
			else q[a].pop_back();
		}
		if(s=="push_front"){
			int a,x;
			cin>>a>>x;
			q[a].push_front(x);
		}
		if(s=="pop_front"){
			int a;
			cin>>a;
			if(q[a].empty())
			continue;
			else q[a].pop_front();
		}
		if(s=="size"){
			int a;
			cin>>a;
			if(q[a].empty())
			continue;
			else cout<<q[a].size()<<endl;
		}
		if(s=="front"){
			int a;
			cin>>a;
			if(q[a].empty()) continue;
			else cout<<q[a].front()<<endl;
		}
		if(s=="back"){
			int a;
			cin>>a;
			if(q[a].empty()) continue;
			else cout<<q[a].back()<<endl;
		} 
	}
	return 0;
}