#include <bits/stdc++.h>
using namespace std;
int main() {
  ios::sync_with_stdio(false);
  int upp = 0, low = 0;
  string s;
  cin >> s;
  int n = s.length();
  for (int i = 0; i < int(n); ++i)
    if (s[i] < 'a')
      upp++;
    else
      low++;
  if (upp > low) {
    for (int i = 0; i < int(n); ++i)
      if (s[i] >= 'a' && s[i] <= 'z') s[i] -= 'z' - 'Z';
  } else {
    for (int i = 0; i < int(n); ++i)
      if (s[i] >= 'A' && s[i] <= 'Z') s[i] += 'z' - 'Z';
  }
  cout << s;
  return 0;
}
