#include <bits/stdc++.h>
using namespace std;
int main() {
  int i, j, k, n;
  string s;
  cin >> s;
  int upc = 0, lwc = 0;
  for (i = 0; s[i] != '\0'; i++) {
    if (s[i] >= 'A' && s[i] <= 'Z')
      upc++;
    else
      lwc++;
  }
  if (lwc == upc) {
    for (i = 0; s[i] != '\0'; i++) {
      s[i] = tolower(s[i]);
      cout << s[i];
    }
  } else if (lwc > upc) {
    for (i = 0; s[i] != '\0'; i++) {
      s[i] = tolower(s[i]);
      cout << s[i];
    }
  } else {
    for (i = 0; s[i] != '\0'; i++) {
      s[i] = toupper(s[i]);
      cout << s[i];
    }
  }
  return 0;
}
