#include <bits/stdc++.h>
using namespace std;

#define FAST_CC ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
#define fi first
#define se second
#define pb push_back
#define RESET(s, x) memset(s, x, sizeof(s))

typedef long long ll;
typedef vector<int> vi;
typedef pair<int, int> ii;
typedef vector<ii> vii;
typedef vector<int, vii > viii;

const double PI = acos(-1.0);
const double EPS = 1e-9;
const int MOD = 1e9 + 7;
const int INF = 1e9;
const long long INFLL = 4e18;
const int dr[] = {-1, 0, 1, 0, -1, 1, 1, -1};
const int dc[] = {0, 1, 0, -1, 1, 1, -1, -1};

bool isspec(char c) {
	string special = "!@#$%^&*()-+";
	for (int i = 0; i < special.length(); i++) {
		if (c == special[i]) return true;
	}
	return false;
}

int main() {
	FAST_CC
	int n;
	cin >> n;
	string s;
	cin >> s;

	int lc, uc, dig, spec;
	lc = uc = dig = spec = 0;

	for (int i = 0; i < n; i++) {
		if (islower(s[i])) lc++;
		else if (isupper(s[i])) uc++;
		else if (isdigit(s[i])) dig++;
		else if (isspec(s[i])) spec++;
	}
	int need = 0;
	if (lc < 1) need++;
	if (uc < 1) need++;
	if (dig < 1) need++;
	if (spec < 1) need++;
	//printf("%d %d %d %d %d\n", lc, uc, dig, spec, need);
	if (n + need < 6) need += (6 - n - need);
	//printf("%d %d %d %d %d\n", lc, uc, dig, spec, need);
	printf("%d\n", need);
	return 0;
}