#include <stdio.h>
#include <vector>
#include <algorithm>

using namespace std;

int main() {

  // Get input
  int N;
  scanf("%d\n", &N);
  std::vector< int > values (N);
  std::vector< char > suits (N);
  scanf("%c%d", &suits[0], &values[0]);
  for(int i = 1; i < N; i++) {
    scanf(" %c%d", &suits[i], &values[i]);
  }

  // Go over all valid suit permutations
  int best_lis = 0;
  vector< char > suit_order {'E', 'R', 'S', 'W', 'C'};
  do {

    // Translate the hand to integers with the same relative order
    vector< int > hand (N);
    for (int i=0; i<N; i++) {
      hand[i] = N * (find(suit_order.begin(), suit_order.end(), suits[i]) - suit_order.begin()) + values[i];
    }
    int SUPERIOR = 6*N;

    // Compute LIS (longest increasing subsequence)
    vector< int > lis_aux (hand.size() + 1, SUPERIOR); // position i will contain the smallest value that ends an increasing subsequence of length i+1 (or SUPERIOR if no such sequence exists)
    for (auto i=hand.begin(); i<hand.end(); i++) {
      auto j = upper_bound(lis_aux.begin(), lis_aux.end(), *i);
      *j = *i;
    }
    int lis = find(lis_aux.begin(), lis_aux.end(), SUPERIOR) - lis_aux.begin();
    
    // Take the best LIS over all suit orders
    best_lis = max(best_lis, lis);
  } while (next_permutation(suit_order.begin(), suit_order.end() - 1));

  // All cards not in the LIS should be moved
  printf("%d\n", N - best_lis);

  return 0;
}