#include <iostream>
#include <fstream>
#include <vector>
#include <string>
using namespace std;
int main()
{
    ifstream cin("set.in");
    ofstream cout("set.out");
    string s;
    vector <vector<int>> a(1e6 + 7);
    int t;
    bool flag;
    while (cin >> s)
    {
        cin >> t;
        if (s[0] == 'i')
        {
            flag = false;
            for (int i = 0; i < a[abs(t) % 1000007].size(); i++)
                if (a[abs(t) % 1000007][i] == t) flag = true;
            if(flag==false)
                a[abs(t) % 1000007].push_back(t);
        }
        else if (s[0] == 'e')
        {
            flag = false;
            for (int i = 0; i < a[abs(t) % 1000007].size(); i++)
                if (a[abs(t) % 1000007][i] == t) { flag=true; break; }
            if (flag)
                cout << "true\n";
            else
            cout << "false\n";
        }
        else if (s[0] == 'd')
        {
            for (auto i = a[abs(t) % 1000007].begin(); i != a[abs(t) % 1000007].end(); i++)
                if (*i == t) {
                    a[abs(t) % 1000007].erase(i);
                    break;
                }
        }
    }
    return 0;
}