#include <set>
#include <iostream>
#include <string>
#include <vector>

using namespace std;

const long long int inf = 1000000000;

int find(set<long long int> a, long long int x)
{
	/*
	int mi = 1000000001;
	for (auto i : a)
		if (i < mi && i >= x)
			mi = i;
	if (mi == 1000000001)
		return -1;
	return mi;
	*/
	auto e = a.lower_bound(x);
	if (e == a.end())
		return -1;
	return *e;

}

int main()
{
	set<long long int> a;
	long long int n, x, y;
	char ch, ch1;
	cin >> n;
	bool flag = false;
	for (long long int i = 0; i < n; ++i)
	{
		cin >> ch >> x;
		if (ch == '?')
		{
			flag = true;
			ch = '?';
			auto y1 = a.lower_bound(x);
			if (y1 == a.end()) y = -1; else y = *y1;
			cout << y << endl;
		}

		if (ch == '+') {
			if (flag)
				a.insert((x + y) % (inf));
			else
				a.insert(x);
			flag = false;
		}

	}
}