#include <bits/stdc++.h>

using namespace std;

int minimumNumber(int n, string s) {
    // Return the minimum number of characters to make the password strong
    string s1="!@#$%^&*()-+";
    int count=0;
    int flag=0;
        for(char ch='a';ch<='z';ch++){
            for(int i=0;i<s.length();i++){
                if(ch==s[i]){count++;flag=1;break;}
            }
                if(flag==1){break;}
        }
        flag=0;
    for(char ch='A';ch<='Z';ch++){
            for(int i=0;i<s.length();i++){
                if(ch==s[i]){count++;flag=1;break;}
            }
                if(flag==1){break;}
        }
    flag=0;
            for(int i1=0;i1<s1.length();i1++){
                for(int i=0;i<s.length();i++){
                    if(s1[i1]==s[i]){count++;flag=1;break;}
                }
                    if(flag==1){break;}
            }
    flag=0;
    for(int i=0;i<=9;i++){
        for(int j=0;j<s.length();j++ ){
            int  x=s[j]-'0';
            if(x==i){
                count++;
                flag=1;
                break;
            }
        }
        if(flag==1){
            break;
        }
    }
                if(s.length()>6){return 4-count;}
    else{
               int p=4-count;
                p=p+s.length();
            if(p>6){return 4-count;}
        else{return 6-s.length();}
}}

int main() {
    int n;
    cin >> n;
    string password;
    cin >> password;
    int answer = minimumNumber(n, password);
    cout << answer << endl;
    return 0;
}