#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;


int main() {
    int n;
    cin>>n;
    string s;
    cin>>s;
    string numbers = "0123456789";
string lower_case = "abcdefghijklmnopqrstuvwxyz";
string upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
string special_characters = "!@#$%^&*()-+";
    int a=0,b=0,c=0,d=0;
    for(int i=0;i<s.length();i++)
    {
        for(int j=0;j<numbers.length();j++)
        {
            if(s[i]==numbers[j])
                a=1;
        }
         for(int j=0;j<lower_case.length();j++)
        {
            if(s[i]==lower_case[j])
                b=1;
        }
         for(int j=0;j<upper_case.length();j++)
        {
            if(s[i]==upper_case[j])
                c=1;
        }
         for(int j=0;j<special_characters.length();j++)
        {
            if(s[i]==special_characters[j])
                d=1;
        }
    }
    if(s.length()>=6)
    {
        int cnt=0;
        if(a==0)
            cnt++;
        if(b==0)cnt++;
        if(c==0)cnt++;
        if(d==0)cnt++;
        cout<<cnt<<endl;
    }
    else
    {
        int cnt=0;
        if(a==0)
            cnt++;
        if(b==0)cnt++;
        if(c==0)cnt++;
        if(d==0)cnt++;
        cout<<max(cnt,6-int(s.length()))<<endl;
    }
    
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    return 0;
}