#include <bits/stdc++.h>

using namespace std;
string c = "!@#$%^&*()-+";
int minimumNumber(int n, string s) {
    // Return the minimum number of characters to make the password strong
    int u,l,d,sp;
    u=l=sp=d=0;
    for(int i=0;i<n;i++){
        if(s[i]>='A' && s[i]<='Z')
            u=1;
        if(s[i]>='a' && s[i]<='z')
            l = 1;
        if(s[i]>='0' && s[i]<='9')
            d = 1;
        for(int j=0;j<c.length();j++){
            if(s[i]==c[j]){
                sp=1;
                break;
            }
        }
    }
    int sum = 4 - (u+l+d+sp);
    if(n < 6)
        return max(6-n, sum);
    return sum;
}

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