#include <bits/stdc++.h>

using namespace std;

int find(string p){
    int a=0;
    int b=0;
    int c=0;
    int e=0;
    for(int i=0;i<p.length();i++){
        int d=p[i];
        if(d>=97 && d<=122 && b==0){
            b=1;
        }else if(d>=65 && d<=91 && a==0){
            a=1;
        }else if(d>=48 && d<=57 && c==0){
            c=1;
        }
        if(e==0){
            if(p[i]=='!' || p[i]=='@' || p[i]=='#' || p[i]=='$' || p[i]=='%' || p[i]=='^' || p[i]=='&' || p[i]=='*' || p[i]=='(' || p[i]==')' || p[i]=='-' || p[i]=='+'){
            e=1;
            }
        }
        if(a+b+c+e==4){
            return 4;
        }
    }
    return a+b+c+e;
}

int minimumNumber(int n, string password) {
    int d = find(password);
    if(d==4 && n>=6){
        return 0;
    }else if(d<4){
        if(n+4-d>=6){
            return 4-d;
        }else{
            d=4-d;
            return d+6-n-d;
        }
    }else if(d==4 && n<6){
        if(n==4){
            return 2;
        }else{
            return 1;
        }
    }
    return n-6;
}

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