#include <bits/stdc++.h>
using namespace std;
int main() {
  int low = 0, down = 0;
  ;
  string s;
  cin >> s;
  for (int i = 0; i < s.size(); ++i) {
    if (s[i] >= 'a')
      ++low;
    else
      ++down;
  }
  if (down > low) {
    for (int i = 0; i < s.size(); ++i)
      if (s[i] >= 'a') s[i] -= 32;
  } else {
    for (int i = 0; i < s.size(); ++i)
      if (s[i] >= 'A' && s[i] <= 'Z') s[i] += 32;
  }
  cout << s;
  return 0;
}
