#include <bits/stdc++.h>
using namespace std;
void uporlow() {
  string s, a;
  string q = "abcdefghijklmnopqrstuvwxyz";
  string c = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
  int qc = 0, qw = 0;
  cin >> s;
  for (int i = 0; i < s.length(); i++) {
    for (int k = 0; k < 26; k++) {
      if (s[i] == q[k]) {
        qw++;
      }
      if (s[i] == c[k]) {
        qc++;
      }
    }
  }
  for (int i = 0; i < s.length(); i++) {
    for (int k = 0; k < 26; k++) {
      if (qw < qc) {
        if (s[i] == q[k] || s[i] == c[k]) {
          a += c[k];
        }
      }
      if (qw > qc || qw == qc) {
        if (s[i] == q[k] || s[i] == c[k]) {
          a += q[k];
        }
      }
    }
  }
  cout << a;
}
int main() {
  uporlow();
  return 0;
}
