#include <bits/stdc++.h>

using namespace std;


int minimumNumber(int n, string password) {
    int no=0;
    int lo=0;
    int up=0;
    int sp=0;
    for(int i=0;i<n;i++){
        if((int) password[i]-'0'>= 0 && (int) password[i]-'0' <=9 )
            no++;
        if(password[i]>='a'&& password[i]<='z')
            lo++;
        if(password[i]>='A' && password[i]<= 'Z')
            up++;
        if(password[i]=='!'|| password[i]=='@'|| password[i]=='#' || password[i]=='$' || password[i]=='%' || password[i]=='^'
          || password[i]=='&' || password[i]=='(' || password[i]==')' || password[i]=='-' || password[i]=='+' )
            sp++;
        
    }
    int tot=0;
    if(n<6){
       if(no==0)tot++;
        if(lo==0)tot++;
        if(up==0)tot++;
        if(sp==0)tot++;
        if(n+tot<6)
            return (6-n);
        else{
            return tot;
        }
    }
    else{
        if(no==0)tot++;
        if(lo==0)tot++;
        if(up==0)tot++;
        if(sp==0)tot++;
    }
     return tot;
}

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