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


int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */
    string numbers,lower_case,upper_case,special_characters;
    numbers = "0123456789";
    lower_case = "abcdefghijklmnopqrstuvwxyz";
    upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    special_characters = "!@#$%^&*()-+";
    unordered_set<char> num,lows,ups,spl;
    for(int i=0;i<numbers.length();i++){
        num.insert(numbers[i]);
    }
    for(int i=0;i<lower_case.length();i++){
        lows.insert(lower_case[i]);
    }
    for(int i=0;i<upper_case.length();i++){
        ups.insert(upper_case[i]);
    }
    for(int i=0;i<special_characters.length();i++){
        spl.insert(special_characters[i]);
    }
    int n;
    cin>>n;
    string inp;
    cin>>inp;
    int count=4;
    bool arr[4];
    for(int i=0;i<4;i++) arr[i]=false;
    
    for(int i=0;i<inp.length();i++){
        if(count==0) break;
        char key=inp[i];
        if(!arr[0] && num.find(key)!=num.end()){ count--; arr[0]=true;}
        if(!arr[1] && lows.find(key)!=lows.end()){ count--; arr[1]=true;}
        if(!arr[2] && ups.find(key)!=ups.end()){ count--; arr[2]=true;}
        if(!arr[3] && spl.find(key)!=spl.end()){ count--; arr[3]=true;}        
    }
    if(count==0){
        if(n>=6) cout<<0<<"\n";
        else cout<<6-n<<"\n";
    }
    else{
        if(n>=6) cout<<count<<"\n";
        else cout<<max(6-n,count)<<"\n";
    }
    
    return 0;
}