include

include

include

include

using namespace std;

// Function to convert HH:MM:SS to total seconds int timeToSeconds(const string& time) { int h = stoi(time.substr(0, 2)); int m = stoi(time.substr(3, 2)); int s = stoi(time.substr(6, 2)); return h * 3600 + m * 60 + s; }

// Function to convert seconds to HH:MM:SS string secondsToTime(int seconds) { int h = seconds / 3600; seconds %= 3600; int m = seconds / 60; int s = seconds % 60; ostringstream oss; oss << setw(2) << setfill('0') << h << ":" << setw(2) << setfill('0') << m << ":" << setw(2) << setfill('0') << s; return oss.str(); }

int main() { int n; cin >> n; vector times(n); vector> converted; // (seconds, original_string)

for (int i = 0; i < n; ++i) {
    cin >> times[i];
    converted.push_back({timeToSeconds(times[i]), times[i]});
}

// Sort by seconds
sort(converted.begin(), converted.end());

int min_diff = INT_MAX;
vector<pair<string, string>> result;

for (int i = 1; i < n; ++i) {
    int diff = converted[i].first - converted[i - 1].first;
    if (diff < min_diff) {
        min_diff = diff;
        result.clear();
        result.push_back({converted[i - 1].second, converted[i].second});
    } else if (diff == min_diff) {
        result.push_back({converted[i - 1].second, converted[i].second});
    }
}

// Print results
for (auto& interval : result) {
    cout << interval.first << "->" << interval.second << endl;
}

return 0;

}