#include <cmath>
#include <iostream>
using namespace std;

int main() {
  int n;
  scanf("%d", &n);

  string s;
  cin >> s;

  bool checked[5] = {false};

  int sz = s.size();

  if (sz > 5) checked[0] = true;

  for (int i = 0; i < sz; i++)
  {
    int x = s[i];

    if (47 < x && x < 58)
      checked[1] = true;
    else if (64 < x && x < 91)
      checked[2] = true;
    else if (96 < x && x < 123) checked[3] = true;
    else
      checked[4] = true;
  }

  int sum = 0;
  for (bool v : checked) sum += (int) v;

  int t = 5 - sum;

  if (t <= 6 - sz) t = 6 - sz;

  if (t > 6 - sz) t = 5 - sum - 1;

  if (sz > 5) t = 5 - sum;

  printf("%d\n", t);

  return 0;
}