#include<cstdio>
#include<cstring>
#include<string>
#include<iostream>
#include<algorithm>
using namespace std;

int n;
bool tong[10000], f[5];
const string ch = "!@#$%^&*()-+";
string s;

int main()
{
	for (int i = 0; i < ch.size(); i ++)
		tong[ch[i]] = 1;
	scanf("%d", &n);
	cin >> s; int l = s.size();
	for (int i = 0; i < l; i ++){
		if (isdigit(s[i])) f[0] = true;
		if (s[i] >= 'a' && s[i] <= 'z') f[1] = true;
		if (s[i] >= 'A' && s[i] <= 'Z') f[2] = true;
		if (tong[s[i]]) f[3] = true;
	} int ans = 0;
	for (int i = 0; i < 4; i ++) if (!f[i]) ans ++;
	ans = max(ans, 6-l);
	printf("%d\n", ans);
	return 0;
}