/*
	Name: Harshit Jain
	Institution: IIIT Vadodara
*/
#include <iostream>
#include <vector>
#include <set>
#include <algorithm>
#include <list>
#include <stack>
#include <cstring>
#include <map>
#include <queue>
#include <ctime>
#include <set>
#include <sstream>
#include <unordered_set>
#include <unordered_map>
#include <cmath>
#include <climits>

#define trace2(x, y)             cout <<#x<<": "<<x<<" | "<<#y<<": "<<y<< endl;
#define trace3(x, y, z)          cout <<#x<<": "<<x<<" | "<<#y<<": "<<y<<" | "<<#z<<": "<<z<<endl;
#define trace4(a, b, c, d)       cout <<#a<<": "<<a<<" | "<<#b<<": "<<b<<" | "<<#c<<": "<<c<<" | "<<#d<<": "<<d<<endl;
#define trace5(a, b, c, d, e)    cout <<#a<<": "<<a<<" | "<<#b<<": "<<b<<" | "<<#c<<": "<<c<<" | "<<#d<<": "<<d<<" | "<<#e<<": "<<e<<endl;
#define pb push_back
#define mp make_pair
#define ll long long
#define IOS ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#define ull unsigned long long
#define rep(i,a,b) for(ll i = a; i < b; ++i)
#define sz(a) int((a).size()) 
#define pb push_back 
#define all(c) (c).begin(),(c).end() 
#define tr(c,i) for(typeofa((c).begin() i = (c).begin(); i != (c).end(); i++) 
#define present(c,x) ((c).find(x) != (c).end()) 
#define cpresent(c,x) (find(all(c),x) != (c).end()) 
#define p(a) cout << a << "\n";
#define p1(a) cout << a << " ";

#define PI 3.141592653589793
#define MOD (ll)(1e9 + 7)
#define m(a) ((a)%MOD)

using namespace std;
typedef vector<int> vi; 
typedef vector<vi> vvi; 
typedef pair<int,int> ii; 
//=======================

bool isSpecialChar(char c)
{
	string s = "!@#$%^&*()-+";
	rep(i,0,s.length())
	{
		if(s[i] == c)
			return true;
	}
	return false;
}

void solve()
{
	int n;
	cin >> n;
	string s;
	cin >> s;
	int arr[4];
	memset(arr,0,sizeof(arr));
	rep(i,0,n)
	{
		if((int)s[i] >= 48 && (int)s[i] <= 57)
		{
			++arr[0];
		}
		else if((int)s[i] >= 97 && (int)s[i] <= 122)
		{
			++arr[1];
		}
		else if((int)s[i] >= 65 && (int)s[i] <= 90)
		{
			++arr[2];
		}
		else if(isSpecialChar(s[i]))
		{
			++arr[3];
		}
	}
	int ans = 0;
	rep(i,0,4)
	{
		if(arr[i] == 0)
		{
			++ans;
		}
	}
	if(ans + n < 6)
	{
		ans += 6 - ans - n;
	}
	p(ans)
}

//=======================
int main()
{
	bool testing = false;
	IOS
	if(testing)
	{
		freopen("test.txt","rt",stdin);
		int start = clock();
		solve();
		int end = clock();
		cout << "time: " << (end - start)/(double)(CLOCKS_PER_SEC)*1000 << " milliseconds\n";
	}
	else
	{
		solve();
	}
}