#include <bits/stdc++.h>

using namespace std;

int main() {
    
    int n,diff,answer;
    int upper = 1, lower = 1, number = 1, special = 1;
    cin >> n;
    string str;
    cin >> str;
    
        for (int i = 0; i < n; i++)
    {
        if (str[i] >= 'A' && str[i] <= 'Z')
            upper=0;
        else if (str[i] >= 'a' && str[i] <= 'z')
            lower=0;
        else if (str[i]>= '0' && str[i]<= '9')
            number=0;
        else 
            special=0;
    }
   

    if(n>=6)
        answer=upper+lower+number+special;
    else{
        diff=upper+lower+number+special;
        answer=6-n;
        if(answer<diff)
            answer=diff;
    }
    cout << answer << endl;
    return 0;
}