#include <algorithm>
#include <bitset>
#include <cassert>
#include <climits>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <deque>
#include <iomanip>
#include <iostream>
#include <map>
#include <numeric>
#include <list>
#include <queue>
#include <set>
#include <stack>
#include <string>

//long long int: -9,223,372,036,854,775,807 to 9,223,372,036,854,775,807

#define ll          long long
//#define push_back   emplace_back          
#define mp          make_pair
#define pii         pair<int,int>
#define vi          vector<int>
#define all(a)      (a).begin(),(a).end()
#define F           first
#define S           second
#define sz(x)       (int)x.size()
#define hell        1000000007
#define endl        '\n'
#define rep(i,a,b)	for(int i=a;i<b;i++)
#define fill(c,val) memset(c,val,sizeof(c))
#define tests 		int t; cin>>t; while(t--)
using namespace std;
void solve()
{
	int n;
	cin>>n;
	string s;
	cin>>s;
	string a = "0123456789";//10
	string b = "abcdefghijklmnopqrstuvwxyz";
	string c = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";//26
	string d = "!@#$%^&*()-+";//12
	if(n<=3)
	{
		cout<<6-n;
		return;
	}
	int missing=0;
	if(n<6)
	{
		missing=6-n;
	}
	vector<int> found(4);
	for(int i=0;i<n;i++)
	{
		for(int j=0;j<10;j++)
		{
			if(s[i]==a[j])
			{
				found[0]=1;
				break;
			}
		}
		for(int j=0;j<26;j++)
		{
			if(s[i]==b[j])
			{
				found[1]=1;
				break;
			}
			if(s[i]==c[j])
			{
				found[2]=1;
				break;
			}
		}
		for(int j=0;j<12;j++)
		{
			if(s[i]==d[j])
			{
				found[3]=1;
				break;
			}
		}
	}
	int missval=found[0]+found[1]+found[2]+found[3];
	missval=4-missval;
	cout<<max(missval,missing);
}
int main()
{
	ios_base::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
	//tests
	{
		solve();
	}
	return 0;
}