#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <algorithm>
#include <vector>
#include <iostream>
#include <limits.h>
#include <math.h>
#include <string>
#include <assert.h>
using namespace std;

#define ran(i, a, b) for ((i) = (a); (i) < (b); (i)++)
#define rep(i, a) ran ((i), 0, (a))
#define rep1(i, a) ran ((i), 1, (a)+1)
typedef pair<int, int> ii;
typedef vector<int> vi;
typedef vector<ii> vii;
typedef long long ll;
#define _0 first
#define _1 second
#define _pb(x) push_back(x)
#define _mp(x, y) make_pair(x, y)
#if defined(SHIROKO1_LOCAL) && !defined(NDEBUG)
#define DEBUG(...) fprintf(stderr, "[DEBUG] " __VA_ARGS__)
#else
#define DEBUG(...) ((void)0)
#endif



int main()
{
	const char *numbers = "0123456789";
	const char *lower_case = "abcdefghijklmnopqrstuvwxyz";
	const char *upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
	const char *special_characters = "!@#$%^&*()-+";

	int n;
	cin >> n;
	string s;
	cin >> s;
	int lc = 0;
	int uc = 0;
	int sc = 0;
	int dc = 0;
	for (char c : s) {
		if (strchr(numbers, c)) dc = 1;
		if (strchr(lower_case, c)) lc = 1;
		if (strchr(upper_case, c)) uc = 1;
		if (strchr(special_characters, c)) sc = 1;
	}
	int m = max(6, n + (4 - lc - uc - sc - dc));
	cout << (m - n) << endl;
	return 0;
}