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

bool isUpper(char c){
    if(c>=65&&c<=90)
        return true;
    return false;
}

bool isLower(char c){
    if(c>=97&&c<=122){
        return true;
    }
    return false;
}

bool isDigit(char c){
    if(c-'0'>=0&&c-'0'<=9)
        return true;
    return false;
}

bool isSpecial(char c){
    string special_characters = "!@#$%^&*()-+";
    for(int i=0;i<special_characters.length();i++){
        if(c==special_characters[i])
            return true;
    }
    return false;
}

int pwd(string s){
    string numbers = "0123456789";
    string lower_case = "abcdefghijklmnopqrstuvwxyz";
    string upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    string special_characters = "!@#$%^&*()-+";
    
    int present[4] = {0,0,0,0};
    int ans=0;
    int count=0;
    for(int i=0;i<s.length();i++){
        if(isDigit(s[i])){
            present[0]=1;
        } else if(isLower(s[i])){
            present[1]=1;
        } else if(isUpper(s[i])){
            present[2]=1;
        } else if(isSpecial(s[i])){
            present[3]=1;
        }
    }
    for(int i=0;i<4;i++){
        if(present[i])
            count++;
    }
    if(count==4){
        if(s.length()>=6){
            return 0;
        }
        if(s.length()<6){
            return 6-s.length();
        }
    }
    if(s.length()>=6){
        return 4-count;
    }
    if(4-count+s.length()<6){
        return (4-count)+(6-s.length()-4+count);
    } else {
        return 4-count;
    }
    
    
}

int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */
    int len;
    string s;
    cin>>len;
    cin>>s;
    cout<<pwd(s);
    return 0;
}