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;
}