#include<bits/stdc++.h>
#include <iostream>

using namespace std;


int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    int n;
    map<char, bool> map;
    map['!']= true;
    map['@']= true;
    map['#']= true;
    map['$']= true;
    map['%']= true;
    map['^']= true;
    map['&']= true;
    map['*']= true;
    map['(']= true;
    map[')']= true;
    map['-']= true;
    map['+']= true;
    
    cin>>n;
    string s;
    cin>> s;
    bool low, up, digit, spec;
    low= false;
    up= false;
    digit= false;
    spec= false;
    //cout<< s;
    for(int i=0; i< n; i++){
        if(s[i]>= 'a' && s[i]<= 'z')
            low= true;
        else if(s[i]>= 'A' && s[i]<= 'Z')
            up= true;
        else if(s[i]>= '0' && s[i]<= '9')
            digit= true;
        else if(map.find(s[i])!= map.end())
            spec= true;
       
    }
    int  count= 0;
    if(n>=6 && up && low && digit && spec)
        cout<< 0<< endl;
    else{
       //cout<< up;
        if(!up)
            count++;
        if(!low)
            count++;
        if(!digit)
            count++;
        if(!spec)
            count++;
        if(n+count<6)
            count+= 6-n-count;
        
        cout<< count<< endl;
    }
    return 0;
}