#include<bits/stdc++.h>
using namespace std;
int main()
{
	int n;
	cin>>n;
	queue<int> q;
	for(int i=1;i<=n;i++)
	{
		string s;
		cin>>s;
		if(s=="push")
		{
			int x;
			cin>>x;
			q.push(x);
		}
		else if(s=="pop")
		{
			q.pop();
		}
		else if(s=="empty")
		{
			if(!q.empty())
			{
				cout<<"NO"<<endl;
			}
			else{ //空
				cout<<"YES"<<endl;
			}
		}
		else
		{
			cout<<q.front()<<endl;	
		}
	}
	return 0;
}