贪心，维护最靠左的右端点以及最靠右的左端点

// Problem: D. In Love
// Contest: Codeforces - Codeforces Round 905 (Div. 3)
// URL: https://codeforces.com/contest/1883/problem/D
// Memory Limit: 256 MB
// Time Limit: 2000 ms
// 
// Powered by CP Editor (https://cpeditor.org)

#include<bits/stdc++.h>
using namespace std;
using ll=long long;
const int N = 2e5+10;
multiset<ll>L,R;


bool check(){
	if(L.size()<=1)return false;
	return *(R.begin())<*(--L.end());
	
}

void solve()
{
	char c;ll l,r;cin>>c>>l>>r;
	if(c=='+'){
		L.insert(l),R.insert(r);
		
	}else{
		//cout<<l<<" "<<r<<"\n";
		L.erase(L.find(l));
		R.erase(R.find(r));
	}
	
	if(check())cout<<"YES"<<"\n";
	else cout<<"NO"<<"\n";
	
	
}

int main()
{
	ios::sync_with_stdio(0),cin.tie(0),cout.tie(0);
	int _;cin>>_;
	while(_--)solve();
	return 0;
}