#include <iostream>
#include <vector>
#include <string>
#include <iomanip>
#include <queue>
#include <cmath>
#include <algorithm>
#include <tuple>
#include <iomanip>
#include <stdio.h>
#include <map>
#include <bitset>
#include <set>
#include <stack>
#include <queue>
#include <unordered_set>
#include <cassert>
#include <stdlib.h>
#include <time.h>
#include <random>


//#pragma GCC optimize("Ofast,no-stack-protector")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,tune=native")
//#pragma GCC optimize("unroll-loops")
//#pragma GCC optimize("fast-math")
//#pragma GCC optimize("section-anchors")
//#pragma GCC optimize("profile-values,profile-reorder-functions,tracer")
//#pragma GCC optimize("vpt")
//#pragma GCC optimize("rename-registers")
//#pragma GCC optimize("move-loop-invariants")
//#pragma GCC optimize("unswitch-loops")
//#pragma GCC optimize("function-sections")
//#pragma GCC optimize("data-sections")
//#pragma GCC optimize("branch-target-load-optimize")
//#pragma GCC optimize("branch-target-load-optimize2")
//#pragma GCC optimize("btr-bb-exclusive")


#define int long long
#define ll long long
#define ull unsigned long long
#define all(a) a.begin(), a.end()
#define pii pair<int, int>
#define pb push_back
#define ld long double


using namespace std;

const int INF = 1e17;
//const int mod = 2600000069;
//const int p = 179;

struct node{
    node *l, *r;
    int x, y = rand();
    node() {
        x = -1;
        l = r = nullptr;
    }
    node(int x_) {
        x = x_;
        l = r = nullptr;
    }
};

typedef node* pnode;

vector<node> a(300000);
int ind = 0;

pnode merge(pnode a, pnode b) {
    if (!a) return b;
    if (!b) return a;
    if (a->y > b->y) {
        a->r = merge(a->r, b);
        return a;
    } else {
        b->l = merge(a, b->l);
        return b;
    }
}

void split(pnode a, int x, pnode& l, pnode& r) {
    if (!a) {
        l = r = nullptr;
        return;
    }
    if (a->x < x) {
        split(a->r, x, l, r);
        a->r = l;
        l = a;
    } else {
        split(a->l, x, l, r);
        a->l = r;
        r = a;
    }
}


pnode root = nullptr;

int left_most(pnode t) {
    if (t->l) {
        return left_most(t->l);
    } else return t->x;
}

bool check(pnode cur, int x) {
    if (!cur) return 0;
    if (cur->x == x) return 1;
    if (cur->x > x) {
        return check(cur->l, x);
    } else return check(cur->r, x);
}

void add(int x) {
    if (check(root, x)) return;
    pair<pnode, pnode> q;
    split(root, x, q.first, q.second);
    pnode t = &a[ind++];
    t->x = x;
    root = merge(q.first, merge(t, q.second));
}

int last = 0;


void next(int x) {
    pair<pnode, pnode> q;
    split(root, x, q.first, q.second);
    if (!q.second) {
        last = -1;
    } else {
        last = left_most(q.second);
    }
    root = merge(q.first, q.second);
    cout << last << "\n";
}

signed main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    int n;
    cin >> n;
    char t;
    int x;
    while (n--) {
//        for (int i = 0; i < ind; i++) {
//            cout << a[i].x << " " << a[i].y << "\n";
//        }
        cin >> t >> x;
        if (t == '+') {
            add((x + last)%1000000000);
        } else {
            next(x);
        }
    }
}
/*

*/