#include <bits/stdc++.h>
#include <sys/resource.h>

using namespace std;

inline void Boost() {
	ios::sync_with_stdio(false);
	cin.tie(NULL); cout.tie(NULL);
}
typedef long long int ll;
typedef long double ld;

int main() {
	Boost();

	int n;
	cin >> n;
	string s;
	cin >> s;

	bool up, lo, num, spec;
	up = lo = num = spec = false;
	for(int i = 0; i < n; ++i) {
		if('a' <= s[i] && s[i] <= 'z') {
			up = true;
			continue;
		}
		if('A' <= s[i] && s[i] <= 'Z') {
			lo = true; 
			continue;
		}
		if(isdigit(s[i])) {num = true; continue;}
		spec = true;
	}

	int need = 0;
	if(up == false) need++;
	if(lo == false) need++;
	if(num == false) need++;
	if(spec == false) need++;
	
	if(n <= 6) {
		cout << max(6 - n, need);
	} else {
		cout << need;
	}
	return 0;
}