#include <bits/stdc++.h>
using namespace std;
string s, s1, s2;
int main() {
  cin >> s;
  int counter = 0;
  for (int i = 0; i < s.size(); i++) {
    if (islower(s[i])) counter++;
    s1 += tolower(s[i]);
    s2 += toupper(s[i]);
  }
  int b = s.size() - counter;
  if (counter >= b)
    cout << s1;
  else
    cout << s2;
  return 0;
}
