#include <bits/stdc++.h>

using namespace std;

int minimumNumber(int n, string a) {
    int l=0,u=0,s=0,d=0;
    for(int i=0;i<n;i++)
    {
        if(a[i]>='0'&&a[i]<='9')
            d=1;
        else if(a[i]>='a'&&a[i]<='z')
            l=1;
        else if(a[i]>='A'&&a[i]<='Z')
            u=1;
        else if(a[i]=='!'||a[i]=='@'||a[i]=='#'||a[i]=='$'||a[i]=='%'||a[i]=='^'||a[i]=='&'||a[i]=='*'||a[i]=='('||a[i]==')'||a[i]=='-'||a[i]=='+')
            s=1;
    }
        if(n>=6&&(d!=1||l!=1||u!=1||s!=1))
        return (4-(d+l+s+u));
        else if(n<6||(d!=1||l!=1||u!=1||s!=1))
        {
            if(6-n>4-(d+l+s+u))
                return(6-n);
            else
                return(4-(d+l+s+u));
        }
        else
            return 0;
}

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