#include <algorithm>
#include <cmath>
#include <iostream>
#include <map>
#include <string>
#include <vector>
#include <set>

using namespace std;



int main() {
    unordered_map <int, set <int>> kek;

    int query_count;
    cin >> query_count;

    for (int query_id = 0; query_id < query_count; ++query_id) {
        string query_type;
        cin >> query_type;
        int start, finish;
        cin >> start >> finish;
        if (query_type == "ADD") {
            kek[start].insert (finish);
            kek[finish].insert (start);
        } else if (query_type == "GO") {
            int mn = abs (start - finish);
            if (kek.count (start)) {
                auto it = kek[start].lower_bound(finish);
                if (it != kek[start].end()) mn = min(mn, abs(*it - finish));
                if (it != kek[start].begin()) {
                    --it;
                    mn = min(mn, abs(*it - finish));
                }
            }
            cout << mn << '\n';
        }
    }

    return 0;
}