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