#include <bits/stdc++.h>


#define inf 0x3f3f3f3f
#define INF 1000111000111000111LL
#define DEBUG(x) cout << '>' << #x << ':' << x << endl;
#define fastIO ios::sync_with_stdio(false);cout.tie(NULL);cin.tie(NULL);
#define endl '\n'
#define pb push_back
#define pf push_front
#define fi first
#define se second
#define MP make_pair
#define MT make_tuple
#define clr(ar) memset(ar, 0, sizeof(ar));

typedef long long int lli;

using namespace std;

ofstream outfile;
ifstream infile;

int main()
{
	infile.open("input.txt");
	outfile.open("output.txt");

	string numbers = "0123456789", lower_case = "abcdefghijklmnopqrstuvwxyz",upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ",special_characters = "!@#$%^&*()-+";

	int n;
	string s;
	cin >> n >> s;
	int tot = 4;
	bool flag1 = false, flag2 = false, flag3 = false, flag4 = false;
	for(int i = 0 ; i < n; ++i){
		for(int j = 0; j < numbers.size() && !flag1; ++j){
			if(s[i] == numbers[j]){
				tot--;
				flag1 = true;
				break;
			}
		}
		for(int j= 0; j < lower_case.size() && !flag2; ++j){
			if(s[i] == lower_case[j]){
				tot--;
				flag2 = true;
				break;
			}
		}
		for(int j = 0; j < upper_case.size() && !flag3; ++j){
			if(s[i] == upper_case[j]){
				tot--;
				flag3 =true;
				break;
			}
		}
		for(int j = 0; j < special_characters.size() && !flag4; ++j){
			if(s[i] == special_characters[j]){
				--tot;
				flag4 = true;
				break;
			}
		}
	}
	
	int len1 = s.size();
	int len = max(0, 6-len1);
	//cout << tot << ' '<< len << "\n";
	cout << max(len, tot) << "\n";
}