#include <bits/stdc++.h>
using namespace std;
#define MOD 1000000007
#define pii pair<int, int>
#define pll pair<long long, long long>
#define V  vector
#define pb  push_back
#define mp  make_pair
#define pq priority_queue
#define FIN(x) freopen(x,"r",stdin)
#define FOUT(x) freopen(x,"w",stdout)
#define ALL(x) x.begin(),x.end()
#define M(a,x) memset(a,x,sizeof(a))
#define S(x) scanf("%d",&x)
#define Sl(x) scanf("%lld",&x)
#define scs(x) scanf("%s",x);
#define SZ(x) (int)x.size()
#define print(x) printf("%d",x);
#define nl printf("\n")
#define fr first
#define se second
#define printl(x) printf("%lld",x)
#define F(i,a,n) for(int i=a;i<n;i++)
#define INF 4000000000000000000LL
#define LL long long

int main() {
	string numbers = "0123456789";
	string lower_case = "abcdefghijklmnopqrstuvwxyz";
	string upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
	string special_characters = "!@#$%^&*()-+";
	int n;
	cin >> n;
	string s;
	cin >> s;
	int cnt[4] = {0};
	for(int i = 0 ; i < n ; i++){
		for(int j = 0 ; j < numbers.size() ; j++){
			if(s[i] == numbers[j]){
				cnt[0] = 1;
			}
		}
		for(int j = 0 ; j < lower_case.size() ; j++){
			if(s[i] == lower_case[j]){
				cnt[1] = 1;
			}
		}
		for(int j = 0 ; j < upper_case.size() ; j++){
			if(s[i] == upper_case[j]){
				cnt[2] = 1;
			}
		}
		for(int j = 0 ; j < special_characters.size() ; j++){
			if(s[i] == special_characters[j]){
				cnt[3] = 1;
			}
		}
    }
		int ans = 0;
		for(int i = 0 ; i < 4 ; i++){
			ans += (cnt[i] == 0);
		}
		if(n+ans >= 6){
			cout << ans << endl;
			return 0;
		}
		else {
			cout << ans + (6-(n+ans)) << endl;
		}
}