#include <bits/stdc++.h>

using namespace std;

int minimumNumber(int n, string password) {
    // Return the minimum number of characters to make the password strong
    int lc=0;
    int uc=0;
    int d=0;
    int sc=0;
    for(int i=0;password[i]!='\0';i++)
    {
        if(password[i]>='a'&&password[i]<='z')
            lc++;
        else if(password[i]>='A'&&password[i]<='Z')
            uc++;
        else if(password[i]>='0'&&password[i]<='9')
            d++;
        //!@#$%^&*()-+
        else                    if(password[i]=='!'||password[i]=='@'||password[i]=='#'||password[i]=='$'||password[i]=='%'||password[i]=='^'||password[i]=='&'||password[i]=='*'||password[i]=='('||password[i]==')'||password[i]=='-'||password[i]=='+')
            sc++;
    }
    int c=0;
        if(lc==0)
            c++;
        if(uc==0)
            c++;
        if(d==0)
            c++;
        if(sc==0)
            c++;
    if(n>=6)
    {
        return c;
    }
    else
    {
        if(6-n>c)
            return 6-n;
        else
            return c;
    }
    
}

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