#include <iostream>
#include <cctype>
#include <string>
#include <map>
#include <cstdio>
using namespace std;

int main() {
    string line;
    map<string, int> wordCount;
    string currentWord = "";

    while (getline(cin, line)) {
        if (line=="")break;
        for (int i = 0; i < line.size(); i++) {
            unsigned char c = line[i];
            if (isalnum(c)) {
                currentWord += tolower(c);
            } else {
                if (!currentWord.empty()) {
                    wordCount[currentWord]++;
                    currentWord = "";
                }
            }
        }
        if (!currentWord.empty()) {
            wordCount[currentWord]++;
            currentWord = "";
        }
    }

    if (!currentWord.empty()) {
        wordCount[currentWord]++;
        currentWord = "";
    }

    int max_count = 0;
    for (map<string, int>::iterator it = wordCount.begin(); it != wordCount.end(); it++) {
        if (it->second > max_count) {
            max_count = it->second;
        }
    }

    cout << max_count << " occurrences" << endl;
    for (map<string, int>::iterator it = wordCount.begin(); it != wordCount.end(); it++) {
        if (it->second == max_count) {
            cout << it->first << endl;
        }
    }

    return 0;
}