#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> ii;
typedef vector<ii> vii;
typedef vector<int> vi;
typedef vector<ll> vll;
#define FOR(i,n) for (i = 0; i < n; ++i)
#define FORK(i,k,n) for (i = k; i <= n; ++i)
#define FORR(i,k,n) for (i = k; i >= n; --i)

#define re(a,b)   memset(a,b,sizeof(a))
#define sz(a)      (int)(a.size())
#define MIN(a,b)     (a) = min((a),(b))
#define MAX(a,b)     (a) = max((a),(b))
#define input(in)    freopen(in,"r",stdin)
#define output(out)  freopen(out,"w",stdout)
#define ALL(a)       a.begin(),a.end()
#define RALL(a)      a.rbegin(),a.rend()
#define LEN(a)       (int)(a.length())

#define FIN(x)       freopen(x,"r",stdin)
#define FOUT(x)      freopen(x,"w",stdout)
#define FCLOSE       {fclose(stdin); fclose(stdout);}

#define fi           first
#define se           second
#define pb           push_back
#define mp           make_pair
#define  M           100001
#define INF          1001001001
// !@#$%^&*()-+
int main()
{
    ios_base::sync_with_stdio(false);cin.tie(0);
    int n,i,j;
    string s;
    cin >> n >> s;
    
    bool b1=false,b2=false,b3=false,b4=false;
    FOR(i,n)
    {
        int y=int(s[i]);
    //    cout << y << "\n";
        if(y>=48 && y<=57)
            b1=true;
        if(y>64 && y<91)
            b2=true;
        if(y>96 && y<123)
            b3=true;
        if(s[i]=='!' || s[i]=='@' || s[i]=='#' || s[i]=='$' || s[i]=='%' || s[i]=='^' || s[i]=='&' || s[i]=='*' || s[i]=='(' ||              s[i]==')' || s[i]=='-' || s[i]=='+')
            b4=true;
    }
    ll ans=0;
 //   cout << b1  <<"  "<<b2 << " " << b3 << " "<< b4 << "\n";
    if(b1==false)
        ans++;
    if(b2==false)
        ans++;
    if(b3==false)
        ans++;
    if(b4==false)
        ans++;
    if(n>=6)
    cout << ans << "\n";
    else
    {
      //  n+=ans;
       // if(n<6)
       //  ans+=(6-n);
          //  cout <<ans;
        int lol=6-n;
        if(lol<=ans)
            cout << ans;
        else
         cout << lol;   
    }
    return 0;
}