#include <iostream>
#include <string>
#include <vector>
#include <algorithm>

using namespace std;

static const char w[] = { (char)0xEF, (char)0xBD, (char)0x97 };

int main() {
	string s;
	cin >> s;
	vector<size_t> wBegins;
	vector<size_t> wEnds;
	vector<size_t> wCounts;
	bool readingW = false;
	size_t nextWIndex = 0;
	size_t wBegin = 0;
	size_t wEnd = 0;
	size_t wCount = 0;
	for (size_t i = 0; i < s.size() + 1; ++i) {
		char ch = s.c_str()[i];
		if (readingW) {
			if (ch == w[nextWIndex]) {
				++nextWIndex;
				if (nextWIndex == 3) {
					nextWIndex = 0;
					wEnd = i + 1;
					++wCount;
				}
			} else {
				if (wCount > 0) {
					wBegins.push_back(wBegin);
					wEnds.push_back(wEnd);
					wCounts.push_back(wCount);
				}
				readingW = false;
			}
		}
		if (!readingW) {
			if (ch == w[0]) {
				readingW = true;
				nextWIndex = 1;
				wBegin = i;
				wCount = 0;
			}
		}
	}
	if (wCounts.size() == 0) {
		return 0;
	}
	size_t maxWCount = *max_element(wCounts.begin(), wCounts.end());
	for (size_t i = 0; i < wCounts.size(); ++i) {
		if (wCounts[i] == maxWCount) {
			if (i == 0) {
				if (wBegins[i] > 0) {
					cout << s.substr(0, wBegins[i]) << endl;
				}
			} else {
				cout << s.substr(wEnds[i - 1], wBegins[i] - wEnds[i - 1]) << endl;
			}
		}
	}
	return 0;
}