#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, a[4] = {};
  cin >> n;
  for (int i = 0; i < n; i++) {
    char c;
    cin >> c;
    a[0] += c == 'U';
    a[1] += c == 'D';
    a[2] += c == 'L';
    a[3] += c == 'R';
  }
  long res = min(a[0], a[1]) * 2 + min(a[2], a[3]) * 2;
  cout << res;
  return 0;
}
