#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  scanf("%d", &n);
  char str[105];
  scanf("%s", str);
  int l = 0, r = 0, u = 0, d = 0;
  for (int i = 0; i < n; i++)
    if (str[i] == 'L')
      l++;
    else if (str[i] == 'R')
      r++;
    else if (str[i] == 'U')
      u++;
    else if (str[i] == 'D')
      d++;
  printf("%d\n", min(l, r) * 2 + min(u, d) * 2);
}
