#include <bits/stdc++.h>

using namespace std;

int minimumNumber(int n, string a) {
    // Return the minimum number of characters to make the password strong
    int c=0,s=0,b=0,d=0,p=0;
    for(int i=0;i<a.length();i++)
    {
        if(isupper(a[i]))
            c=1;
        if(islower(a[i]))
            b=1;
        if(isdigit(a[i]))
            d=1;
        if(a[i]=='!'||a[i]=='@'||a[i]=='#'||a[i]=='$'||a[i]=='%'||a[i]=='^'||a[i]=='&'||a[i]=='*'||a[i]=='('||a[i]=='-'||a[i]=='+')
            s++;
    }
            int x=0;if(a.length()<6){
                p=6-a.length();}
        if(c==0)
            x++;
        if(b==0)
            x++;
        if(d==0)
            x++;
        if(s==0)
            x++;
   // cout<<c<<" "<<b<<" "<<d<<" "<<s<<" "<<p<<" "<<x;
        if(p==0)
            return x;
        else {
            if(x>p)
               return x;
            else return p;
        }
            

}

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