#include <iostream>
#include <vector>
#include <algorithm>
#include <queue>
#include <set>

using namespace std;

struct Event {
    int time_;
    int type; //0 - пришел человек, 1 - парикмахер освободился
    int manNum;
    int parNum;
    Event() {}
    Event(int time_, int type, int manNum, int parNum) :time_(time_), type(type),
        manNum(manNum), parNum(parNum) {}
    bool operator <(const Event& other) {
        return time_ < other.time_ || (time_ == other.time_ && type > other.type);
    }
};

int main() {
    set<Event> ev;
    int N;
    cin >> N;
    for (int i = 0; i < N; ++i) {
        int h, m;
        cin >> h >> m;
        ev.insert(Event(h * 60 + m, 0, i, -1));
    }
    queue<int> q;
    vector<bool> freePar(3, true);
    vector<int> ans(N);
    while (!ev.empty()) {
        Event cur = *ev.begin();
        ev.erase(ev.begin());
        if (cur.type == 0) {
            bool good = false;
            for (int i = 0; i < 3; ++i) {
                if (freePar[i]) {
                    ev.insert(Event(cur.time_ + 30, 1, cur.manNum, i));
                    good = true;
                    freePar[i] = false;
                    break;
                }
            }
            if (!good) {
                q.push(cur.manNum);
            }
        } else {
            ans[cur.manNum] = cur.time_;
            if (q.empty()) {
                freePar[cur.parNum] = true;
            } else {
                int curMan = q.front();
                q.pop();
                ev.insert(Event(cur.time_ + 30, 1, curMan, cur.parNum));
            }
        }
    }
}