// Created by Abhishek Kumar
#include<bits/stdc++.h>
#define FAST_IO ios::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL)
#define ll long long
#define MOD (int)(1e9+7)
#define MAX (int) (1e6+1)
#define C(x) cin>>x
#define CC(X,Y) cin>>x>>y
#define CCC(X,Y,Z) cin>>X>>Y>>Z
#define O(x) cout<<x
#define ENDL cout<<endl
#define loop(i,a,b) for(int i = a; i<b;++i)
#define loops(i,a,b) for(int i = a; i<=b; ++i)
#define pb(x) push_back(x)
#define pii pair<int,int>
#define vs vector<string>
#define li list<int>
#define vs vector<string>
#define ls list<string>
#define pf(x) push_front(x)
#define ppb() pop_back()
#define ppf() pop_front()
#define vpi vector<pii>
#define mp(x,y) make_pair(x,y)
#define vi vector<int>
#define finder(v,a) (find(v.begin(),v.end())!=v.end())
#define msvi map<string,vi>
#define msvs map<string,vs>
#define mii map<int,int>
#define msi map<string,int>
#define isKey(map,key) (map.find(key) != map.end())
#define ff first
#define ss second
#define psi pair<int,string>
#define pis pair<int,string>
#define pivs pair<int,vs>
#define si set<int>
#define mspivs map<string,pivs>
using namespace std;

bool isPrime(ll n)
{
    if(n==2)
        return true;
    if(!(n%2))
        return false;
    for(int i = 3; i<= sqrt(n); i+=2)
            if(!(n%i))
                return false;
    return true;
}

ll gcd(ll a, ll b)
{
    if(b==0)
        return a;
    return ((a>b)?gcd(b,a%b):gcd(a, b%a));
}

int digitSum(ll n)
{
    int sum = 0;
    while(n>0)
    {
        sum+=(n%10);
        n/=10;
    }
    return sum;
}

int main()
{
    FAST_IO;
    int n;
    cin>>n;
    string s;
    cin>>s;
    bool low=false,high=false,spcl=false,dig=false;
    string sym = "!@#$%^&*()-+";
    loop(i,0,n)
    {
        if(islower(s[i]))
            low = true;
        else if(isupper(s[i]))
            high = true;
        else if(isdigit(s[i]))
            dig = true;
        else
            spcl = true;
    }
    int sum = low+high+spcl+dig;
    int w = max(0,4-sum);
    //cout<<low<<" "<<high<<" "<<dig<<" "<<sym <<endl;
    w+=max(0,6-n-w);
    cout<<w;
    return 0;
}