#include <bits/stdc++.h>
#define int long long
using namespace std;
const int N = 2e5 + 228;
const int M = 2e5;
struct hashset {
    vector<int> a[N];

    int get_hash(int x) {
        x = abs(x);
        return x % M;
    }

    void insert(int x) {
        int hash = get_hash(x);
        if (che(x)) return;
        a[hash].push_back(x);
    }
    void del(int x) {
        if (!che(x)) return;
        int hash = get_hash(x);
        for (int i = 0; i < a[hash].size(); ++ i) {
            if (x == a[hash][i]) {
                swap(a[hash][i], a[hash][a[hash].size() - 1]);
                a[hash].pop_back();
                return;
            }
        }
    }
    bool che(int x){
        int hash = get_hash(x);
        for (int i : a[hash]) {
            if (i == x) return true;
        }
        return false;
    }
};

int32_t main() {
    ios_base::sync_with_stdio(0);
    freopen("set.in", "r", stdin);
    freopen("set.out", "w", stdout);
    hashset set;
    string s;
    while (cin >> s) {
        if ( s == "insert") {
            int q;
            cin >> q;
            set.insert(q);
        } else if (s == "delete") {
            int x;
            cin >> x;
            set.del(x);
        } else {
            int x;
            cin >> x;
            bool q = set.che(x);
            if (q)
                cout << "true" << endl;
            else
                cout << "false" << endl;
        }
    }
}