#include <bits/stdc++.h>

using namespace std;

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

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