#include <bits/stdc++.h>

using namespace std;

int minimumNumber(int n, string password) {
	int digit = 0, lower = 0, upper = 0, special = 0;
	for (char s : password) {
		if (isdigit(s)) digit = 1;
		else if (islower(s)) lower = 1;
		else if (isupper(s)) upper = 1;
		else special = 1;
	}
	int types = digit + lower + upper + special;
	int rl = (n > 6?0:6-n);
	return max(4-types, rl);
}

int main() {
    int n;
    cin >> n;
    string password;
    cin >> password;
    int answer = minimumNumber(n, password);
    cout << answer << endl;
    return 0;
}