#include <bits/stdc++.h>
using namespace std;
int main() {
  string s;
  cin >> s;
  int lower = 0, upper = 0;
  for (int i = 0; i < s.size(); i++) {
    if (islower(s[i]))
      lower++;
    else
      upper++;
  }
  if (lower > upper || lower == upper) {
    for (int i = 0; i < s.size(); i++) {
      s[i] = tolower(s[i]);
    }
  } else {
    for (int i = 0; i < s.size(); i++) {
      s[i] = toupper(s[i]);
    }
  }
  cout << s << endl;
}
