#include <bits/stdc++.h>

#define REP(i,n) for(int i=0;i<(int)(n);i++)
#define ALL(x) (x).begin(),(x).end()

using namespace std;

vector<string> utf8(string str) {
  vector<string> res;
  int n = 0;
  for (int i = 0; i < (int)str.size(); i += n) {
    n = 1; unsigned char c = str[i];
    n += (c >= 0x80); n += (c >= 0xE0); n += (c >= 0xF0);
    res.push_back(str.substr(i, n));
  }
  return res;
}

int main() {
  string str; cin >> str; str += "あ";
  int n = 0, ma = 0;
  vector<string> res;
  string s;
  for (string c: utf8(str)) {
    if (c == "ｗ") ++n;
    else {
      if (n > 0 && !s.empty()) {
        if (n > ma) { ma = n; res = {s}; }
        else if (n == ma) res.push_back(s);
        s = "";
      }
      n = 0; s += c;
    }
  }
  for (auto s: res) cout << s << endl;
  return 0;
}