#include <bits/stdc++.h>
using namespace std;

typedef long long ll;

const long long maxn = 1e5+10;
const long long M    = 2017;
const double    eps  = 1e-10;
const double    pi   = atan(1) * 4;

int main() {
    ios_base::sync_with_stdio(false); cin.tie(NULL); 
    //freopen("input.txt", "r", stdin); freopen("output.txt", "w", stdout);
    bool flagnum = false;
    bool flagup  = false;
    bool flaglow = false;
    bool flagspec = false;
    int n;
    string s;
    cin >> n;
    cin >> s;
    for (int i = 0; i < (int)s.length(); i++)
    {
      if (s[i]>=48 && s[i] <= 57) flagnum=true;
      else if (s[i]>=65 && s[i] <= 90) flagup=true;
      else if (s[i]>=97 && s[i] <= 122) flaglow=true;
      else flagspec=true;
    }
    int res = 4 - (flagnum+flagspec+flaglow+flagup);
    if (res + n < 6) res = 6 - n;
    else if (n >= 6 && res == 0) res = 0;
    cout << res; 
    return 0;
}