5A

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cmath>
#include <vector>
#include <string>
#include <set>
#include <stack>
#include <queue>
#include <deque>
using namespace std;

#define TASK "set"

vector < pair < int, bool > > hash_map[1010101];

int hash_f(int x) {
    return (x >= 0 ? x : abs(x)) % 1000000;
}

int ex(int x) {
    int hx = hash_f(x);
    for (int i = 0; i < hash_map[hx].size(); i++) {
        if (hash_map[hx][i].first == x) {
            if (hash_map[hx][i].second)
                return i;
            return ~i;
        }
    }
    return -1e9;
}

void ins(int x) {
    int t = ex(x);
    if (t < 0) {
            int hx = hash_f(x);
        if (t == -1e9) {
            hash_map[hx].push_back(make_pair(x, true));
            return;
        }
        hash_map[hx][~t].second = true;
    }
}

void del(int x) {
    int t = ex(x);
    if (t >= 0) {
        int hx = hash_f(x);
        hash_map[hx][t].second = false;
    }
}

int main() {

#ifdef _DEBUG
    freopen("debug.in", "r", stdin);
    freopen("debug.out", "w", stdout);
#else
    freopen(TASK".in", "r", stdin);
    freopen(TASK".out", "w", stdout);
#endif // _DEBUG

    string s;
    int x;
    while (cin >> s) {
        cin >> x;
        switch (s[0]) {
        case 'i':   ins(x); break;
        case 'd':   del(x); break;
        case 'e':   cout << (ex(x) >= 0 ? "true\n" : "false\n");    break;
        }
    }

    return 0;
}