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


int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */ 
    int a=0,b=0,c=0,d=0;
    int n;
    cin>>n;
    string s;
    string ss = "!@#$%^&*()-+";
    cin>>s;
    int res = 0;
    for(int i=0;i<n;i++){
        if(s[i]-'0' >=0 && s[i]-'0'<=9) a++;
        else if(s[i]-'a' >=0 && s[i]-'a'<=25) b++;
        else if(s[i]-'A' >=0 && s[i]-'A' <=25) c++;
        else if(ss.find(s[i]) != string::npos) d++;
    }
    if(a==0) res++;
    if(b==0) res++;
    if(c==0) res++;
    if(d==0) res++;
    if(n+res < 6) res += 6-n-res;
    cout<<res<<endl;
    return 0;
}