#include<bits/stdc++.h>
using namespace std;
list<int>l[1000010];
char s[20];
int main()
{
	int q;
	scanf("%d",&q);
	while(q--)
	{
		scanf("%s",s);
		if(strcmp(s,"pop_back")==0)
		{
			int x;
			scanf("%d",&x);
			if(!l[x].empty())
			{
				l[x].pop_back();
			}
		}
		if(strcmp(s,"push_back")==0)
		{
			int x,y;
			scanf("%d%d",&x,&y);
			l[x].push_back(y);
		}
		if(strcmp(s,"push_front")==0)
		{
			int x,y;
			scanf("%d%d",&x,&y);
			l[x].push_front(y);
		}
		if(strcmp(s,"pop_front")==0)
		{
			int x;
			scanf("%d",&x);
			if(!l[x].empty())
			{
				l[x].pop_front();
			}
		}
		if(strcmp(s,"size")==0)
		{
			int x;
			scanf("%d",&x);
			printf("%d\n",l[x].size());
		}
		if(strcmp(s,"front")==0)
		{
			int x;
			scanf("%d",&x);
			printf("%d\n",l[x].front());
		}
		if(strcmp(s,"back")==0)
		{
			int x;
			scanf("%d",&x);
			printf("%d\n",l[x].back());
		}  
	}
	return 0;
}