#include<bits/stdc++.h>

#define _USE_MATH_DEFINES
#define ll long long
#define ins Not Needed Thing
#define ull unsigned long long
#define ld long double
#define Accepted 0
#define pb push_back
#define pii pair<int,int>
#define pll pair<ll,ll>
#define mp make_pair
#define sz(x) (int)(x.size())
#define all(x) x.begin(),x.end()
#define F first
#define S second
#define emp What is it
#define SORRY FUL Accepted 
#define dimash the top one
#define I wish 
#define you be a little more calm
#define SpeedForce ios_base::sync_with_stdio(0), cin.tie(0)

using namespace std;

const double eps = 0.000001;
const ld pi = acos(-1);
const int maxn = 1e7 + 9;
const int mod = 1e9 + 7;
const ll MOD = 1e18 + 9;
const ll INF = 1e18 + 123;
const int inf = 2e9 + 11;
const int mxn = 1e6 + 9;
const int N = 5e3 + 123;                                          
const int NN = 5e5 + 123;
const int PRI = 555557;
const int pri = 997;

int tests = 1;
int n, m, k, a[5], cnt, ans;
string s;

bool isspe (char c) {
	string qwe = "!@#$%^&*()-+";
	for (int i = 0; i < qwe.size(); i ++)
		if(qwe[i] == c) return 1;
	return 0;
}

inline void Solve () {
	// easy
	cin >> n;
	cin >> s;

	for (int i = 0; i < n; i ++) {
		if(isspe(s[i])) a[0] = 1;
		if(isdigit(s[i])) a[1] = 1;
		if(islower(s[i])) a[2] = 1;
		if(isupper(s[i])) a[3] = 1;	
	}

	k = !a[0] + !a[1] + !a[2] + !a[3];

	cout << max(k, 6 - n);
}

int main () {
	SpeedForce;
//	freopen(".in", "r", stdin);
//	freopen(".out", "w", stdout);	
	// cin >> tests;
	while(tests --) {
		Solve ();
		// Ee Zadrot
	}	
}