#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;


int main() {
    bool digit = false, upper = false, lower = false, special = false;
    string numbers = "0123456789";
    string lower_case = "abcdefghijklmnopqrstuvwxyz";
    string upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    string special_characters = "!@#$%^&*()-+";
    int size, cnt = 0;
    string str;
    cin >> size >> str;
    for (const auto& c : str) {
        if (numbers.find(c) != str.npos) {
            digit = true;
        } else if (lower_case.find(c) != str.npos) {
            lower = true;
        } else if (upper_case.find(c) != str.npos) {
            upper = true;
        } else if (special_characters.find(c) != str.npos) {
            special = true;
        }
    }
    cnt = 4 - (digit + upper + lower + special);
    cnt = max(6 - size, cnt);
    cout << cnt;
    
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    return 0;
}