#include <bits/stdc++.h>
int main() {
  std::string string;
  std::cin >> string;
  int lower{}, upper{};
  int x = (string.size() + 1) / 2;
  int i = 0;
  while (i != string.size()) {
    int t = string.at(i);
    if (t >= 97)
      lower++;
    else
      upper++;
    if (lower >= x || upper > x) break;
    i++;
  }
  if (lower >= x) {
    for (int i = 0; i < string.size(); i++) {
      int t = (int)string[i];
      if (t <= 90) t += 32;
      string[i] = t;
    }
    std::cout << string;
  } else {
    for (int i = 0; i < string.size(); i++) {
      int t = (int)string[i];
      if (t >= 97) t -= 32;
      string[i] = t;
    }
    std::cout << string;
  }
  std::cout << "\n";
  return 0;
}
