#include <bits/stdc++.h>

using namespace std;

int minimumNumber(int n, string p) {
    int lower=0,upper=0,digit=0,other=0;
    for(int i=0;i<n;i++)
    {
     if(isdigit(p[i])) digit++;
        else if(isalpha(p[i]))
        {
            if(islower(p[i]))
                lower++;
            else
                upper++;
        }
        else other++;
        
    }
    int cnt=0;
    if(!lower) cnt++; if(!upper) cnt++; if(!digit) cnt++; if(!other) cnt++;
    if(n+cnt >=6) return cnt;
    else return 6-n;
    // 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;
}