#include <bits/stdc++.h>

using namespace std;

#define D(x) cout << #x << " " << x << endl

string numbers = "0123456789";
string lower = "abcdefghijklmnopqrstuvwxyz";
string upper = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
string special = "!@#$%^&*()-+";
    
bool isSpecial(string x) {
    size_t found = special.find(x);
    return found != string::npos;
}

bool isNumber(string x) {
    size_t found = numbers.find(x + "");
    return found != string::npos;
}

bool isLower(string x) {
    size_t found = lower.find(x + "");
    return found != string::npos;
}

bool isUpper(string x) {
    size_t found = upper.find(x + "");
    return found != string::npos;
}

int minimumNumber(int n, string pass) {
    vector<bool> conditions(4, false);
    int nConditions = 0;
    for(int i = 0; i < pass.size() && nConditions <= 4; ++i) {
        char currChar = pass[i];
        if(isSpecial(string(1, currChar)) && !conditions[0]) {
            conditions[0] = true;
            nConditions++;
        }
        if(isLower(string(1, currChar)) && !conditions[1]) {
            conditions[1] = true;
            nConditions++;
        }
        if(isUpper(string(1, currChar)) && !conditions[2]) {
            conditions[2] = true;
            nConditions++;
        }
        if(isNumber(string(1, currChar)) && !conditions[3]) {
            conditions[3] = true;
            nConditions++;
        }
    }
    int addConditions = (4 - nConditions);
    return addConditions + max(0, 6 - ((int) pass.size() + addConditions));
}

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