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

int n;
string s;
int f[4];


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 = "!@#$%^&*()-+";
    
    cin >> n;
    cin >> s;
    
    for(int i = 0; i < s.size(); i++){
        for(int j = 0; j < numbers.size(); j++){
            if(numbers[j] == s[i]){
                f[0] = 1;
            }
        }
    }
    
    for(int i = 0; i < s.size(); i++){
        for(int j = 0; j < lower_case.size(); j++){
            if(lower_case[j] == s[i]){
                f[1] = 1;
            }
        }
    }
    
    for(int i = 0; i < s.size(); i++){
        for(int j = 0; j < upper_case.size(); j++){
            if(upper_case[j] == s[i]){
                f[2] = 1;
            }
        }
    }
    
    for(int i = 0; i < s.size(); i++){
        for(int j = 0; j < special_characters.size(); j++){
            if(special_characters[j] == s[i]){
                f[3] = 1;
            }
        }
    }
    
    int answer = (4 - f[0] - f[1] - f[2] - f[3]);
    if(n < 6){
        answer = max(answer, 6-n);
    }
    
    cout << answer << endl;
    
    
        
        
    return 0;
}