#include<bits/stdc++.h>
using namespace std;

int main()
{
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	cout.tie(NULL);

	int N;
	cin >> N;
	string S;
	cin >> S;

	int ans1 = max(6 - N, 0);
	int ans2 = 0;

	bool hasd = false, hasl = false, hasu = false, hass = false;
	for (char ch : S) {
		if ('0' <= ch && ch <= '9') hasd = true;
		else if ('a' <= ch && ch <= 'z') hasl = true;
		else if ('A' <= ch && ch <= 'Z') hasu = true;
		else hass = true;
	}
	ans2 = !hasd + !hasl + !hasu + !hass;
	int ans = max(ans1, ans2);
	cout << ans << endl;
	return 0;
}