#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <bits/stdc++.h>
using namespace std;


int main() {
    int n;
    string s;
    cin>>n>>s;
    string ss[4] = {"0123456789", "abcdefghijklmnopqrstuvwxyz", "ABCDEFGHIJKLMNOPQRSTUVWXYZ", "!@#$%^&*()-+"};
    int a[4] = {0, 0, 0, 0};
    for (int i = 0; i < n; i++)
        for (int j = 0; j < 4; j++)
            for (int l = 0; l < ss[j].size(); l++)
                if (s[i] == ss[j][l])
                    a[j] = 1;
    int ans = 4;
    for (int i = 0; i < 4; i++)
        ans -= a[i];
    ans = max (ans, 6 - n);
    cout<<ans;
    return 0;
}