#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define MOD 1000000007
#define pb push_back
#define mp make_pair
#define ff first
#define ss second
#define INF 0x3f3f3f3f
#define sz(a) int((a).size())
#define all(c) (c).begin(),(c).end()
#define tr(c,i) for(typeof((c).begin()) i = (c).begin(); i != (c).end(); i++)
#define fore(i,a,b) for(ll i=a;i<b;i++)
#define fores(i,a,b) for(ll i=a;i<=b;i++)
#define ford(i,a,b) for(ll i=a;i>=b;i--)
#define present(c,x) ((c).find(x) != (c).end())
typedef vector<ll> vi;
typedef pair<ll,ll> pii;

int main() {
	// your code goes here
	ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
    ll n;
    cin>>n;
    string s;
    cin>>s;
    string numbers = "0123456789";
    string lower_case = "abcdefghijklmnopqrstuvwxyz";
    string upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    string special_characters = "!@#$%^&*()-+";
    ll num[4] = {0};
    fore(i,0,n){
        fore(j,0,numbers.size()){
            if(s[i]==numbers[j]){
                num[0] = 1;
                continue;
            }
        }
        fore(j,0,lower_case.size()){
            if(s[i]==lower_case[j]){
                num[1] = 1;
                continue;
            }
        }
        fore(j,0,upper_case.size()){
            if(s[i]==upper_case[j]){
                num[2] = 1;
                continue;
            }
        }
        fore(j,0,special_characters.size()){
            if(s[i]==special_characters[j]){
                num[3] = 1;
                continue;
            }
        }
    }
    ll cnt = 0;
    fore(i,0,4){
        //cout<<num[i]<<"\n";
        if(num[i] == 0)
            cnt++;
    }
    ll ans = ((6-cnt-n)<=0)?0:(6-cnt-n);
    cout<<cnt+ans;
	return 0;
}