#!/usr/bin/env python3
# -*- coding: utf-8 -*-

import collections
import itertools


W = "ｗ"


def mykey(char):
    if char == W:
        return True
    else:
        return False


def solve(xs):
    words = []
    warai_numbers = []
    for k, g in itertools.groupby(itertools.dropwhile(mykey, xs), mykey):
        if k:
            warai_numbers.append(len(list(g)))
        else:
            words.append("".join(g))
    result = collections.OrderedDict(zip(words, warai_numbers))
    answer = []
    if result:
        max_warai = max(result.values())
        for k, v in result.items():
            if v == max_warai:
                answer.append(k)
    return answer


if __name__ == "__main__":
    answer = solve(input())
    if answer:
        for x in answer:
            print(x)
    else:
        print()