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


int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */  
    string numbers = "0123456789";
string lower_case = "abcdefghijklmnopqrstuvwxyz";
string upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
string special_characters = "!@#$%^&*()-+";
    int n;
    cin>>n;
    string p;
    cin>>p;
    int q=0,r=0,s=0,t=0;
    for(int i=0;i<n;i++){
        for(int j=0;j<numbers.length();j++){
            if(p[i]==numbers[j]){
                q=1;
                break;
            }
        }
        for(int j=0;j<lower_case.length();j++){
            if(p[i]==lower_case[j]){
                r=1;
                break;
            }
        }
        for(int j=0;j<upper_case.length();j++){
            if(p[i]==upper_case[j]){
                s=1;
                break;
            }
        }
        for(int j=0;j<special_characters.length();j++){
            if(p[i]==special_characters[j]){
                t=1;
                break;
            }
        }
        if(q==1 && r==1 && s==1 && t==1){
            break;
        }
    }
    int ans=4-q-r-s-t;
    if(n+ans>=6){
        cout<<ans;
    }
    else{
        cout<<ans+6-(n+ans);
    }
    return 0;
}