#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int n;
  cin >> n;
  string s;
  cin >> s;
  int u = 0, d = 0, l = 0, r = -0;
  for (int i = 0; i < n; i++) {
    if (s[i] == 'U')
      u++;
    else if (s[i] == 'D')
      d++;
    else if (s[i] == 'L')
      l++;
    else if (s[i] == 'R')
      r++;
  }
  int o = abs(l - r);
  int p = abs(d - u);
  cout << (max(l, r) - o) * 2 + (max(d, u) - p) * 2;
}
