#include <bits/stdc++.h>

using namespace std;

int minimumNumber(int n, string s) {
    
    int len=0,u=0,l=0,sp=0,d=0;
    
    for(int i=0;i<n;i++){
        if(isdigit (s[i]) ){ d=1;}
        else if(isupper(s[i])){u=1;}
        else if(islower(s[i])){l=1;}
        else{sp=1; }
        }
    int c=0;
    if(u==0){c++;}
    if(l==0){c++;}
    if(sp==0){c++;}
    if(d==0){c++;}
    n+=c;
    if(n<=6){c+=6-n;}
    return c;
    
    // Return the minimum number of characters to make the password strong
}

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