#include <bits/stdc++.h>
using namespace std;
void upper(string);
void lower(string);
int main() {
  short big = 0;
  string z;
  cin >> z;
  for (short i = 0; i < z.length(); i++) {
    if (isupper(z[i])) big++;
  }
  if (z.length() - big < big)
    upper(z);
  else
    lower(z);
}
void upper(string z) {
  for (short i = 0; i < z.length(); i++) {
    putchar(toupper(z[i]));
  }
}
void lower(string z) {
  for (short i = 0; i < z.length(); i++) {
    putchar(tolower(z[i]));
  }
}
