#include <bits/stdc++.h>

using namespace std;

int minimumNumber(int n, string str) {
    // Return the minimum number of characters to make the password strong
    char ar[] = {'!','@','#','$','%','^','&','(',')','-','+'};
    int ans = 0;
    bool number = false,lower=false,upper=false,special = false;
    for(int i=0;i<n;i++)
    {
        if(str[i]<='z' && str[i]>='a')
        {
            lower=true;
        }
        else if(str[i]<='Z' && str[i]>='A')
        {
            upper = true;
        }
        else if(str[i]<='9' && str[i]>='0')
        {
            number = true;
        }
        else
        {
            for(int j=0;j<11;j++)
            {
                if(str[i]==ar[j])
                {
                    special = true;
                }
            }
        }
    }
    if(!lower)ans++;
    if(!upper)ans++;
    if(!number)ans++;
    if(!special)ans++;
    
    ans = max(ans,6-n);
    
    return ans;
}

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