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

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

string numbers = "0123456789";
string lower_case = "abcdefghijklmnopqrstuvwxyz";
string upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
string special_characters = "!@#$%^&*()-+";
bool pre[4] = {0};
int n;
cin >> n;
string s;
cin >> s;
for(int i=0; i<n; i++)
{
	if(s[i] >= '0' and s[i] <= '9')
	pre[0] = true;
	else if(s[i] >= 'a' and s[i] <= 'z')
	pre[1] = true;
	else if(s[i] >= 'A' and s[i] <= 'Z')
	pre[2] = true;
	else
	pre[3] = true;
} 
int res=0;
for(int i=0; i<4; i++)
if(!pre[i])
res++;
if(res+n < 6)
res += (6-n-res);
cout << res << endl;
return 0;
}