#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
void solve() {
  string s;
  cin >> s;
  int upper = 0, lower = 0;
  for (char c : s) {
    ++(c < 91 ? upper : lower);
  }
  for (int i = 0; i < s.size(); ++i) {
    s[i] = upper > lower ? toupper(s[i]) : tolower(s[i]);
  }
  cout << s << "\n";
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(nullptr);
  solve();
  return 0;
}
