#include <bits/stdc++.h>

using namespace std;

int minimumNumber(int n, string p) {
    // Return the minimum number of characters to make the password strong
    bool l=false,u=false,s=false,d=false;
    for(int i=0;i<p.length();i++){
        if(p[i]>='0'&&p[i]<='9') d=true;
        if(p[i]>='a'&&p[i]<='z') l=true;
        if(p[i]>='A'&&p[i]<='Z') u=true;
        string sp = "!@#$%^&*()-+";
        for(int j=0;j<sp.length();j++) if(p[i]==sp[j]) s=true;
    }
    int cnt=4;
    if(l) cnt--;
    if(u) cnt--;
    if(s) cnt--;
    if(d) cnt--;
    int sz = 6-p.length();
    return max(cnt,sz);
}

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