#include <bits/stdc++.h>
using namespace std;
const long long MAXN = 1e5 + 1, INF = 1e17, MOD = 1e9 + 7;
long long n;
string s, t = "UDRL";
map<char, long long> m;
int32_t main() {
  ios_base::sync_with_stdio(0);
  cin >> n >> s;
  for (long long i = 0; i < n; ++i) {
    m[s[i]]++;
  }
  cout << 2 * (min(m[t[0]], m[t[1]]) + min(m[t[2]], m[t[3]])) << endl;
  return 0;
}
