#include <bits/stdc++.h>
using namespace std;
int main() {
  string s;
  cin >> s;
  int n = s.length();
  int c1 = 0, c2 = 0;
  for (int i = 0; i < n; i++)
    if (s[i] >= 'a' && s[i] <= 'z')
      c1++;
    else
      c2++;
  if (c1 < c2) {
    for (int i = 0; i < n; i++)
      if (s[i] >= 'a' && s[i] <= 'z') s[i] = (s[i] - 'a') + 'A';
  } else {
    for (int i = 0; i < n; i++)
      if (s[i] >= 'A' && s[i] <= 'Z') s[i] = (s[i] - 'A') + 'a';
  }
  cout << s;
  return 0;
}
