#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 with an O(N^2) DP implementation from https://www.geeksforgeeks.org/longest-increasing-subsequence-dp-3/
    int lis_aux[N];
    lis_aux[0] = 1;
    for (int i = 1; i < N; i++) {
        lis_aux[i] = 1;
        for (int j = 0; j < i; j++)
            if (hand[i] > hand[j] && lis_aux[i] < lis_aux[j] + 1)
                lis_aux[i] = lis_aux[j] + 1;
    }
    int lis = *max_element(lis_aux, lis_aux + N);
    
    // 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;
}