#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));
			}
		}
	}
}