#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;


int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */  
    int n;
    cin>>n;
    string a;
    cin>>a;
   // cout<<a<<" ";
    int d=0,s=0,l=0,u=0;
    for(int i=0;i<n;i++ )
    {
        if(int(a[i])>=33&&int(a[i])<=45)
            s++;
        else if(int(a[i])>=48&&int(a[i])<=57)
            d++;
        else if(int(a[i])>=65&&int(a[i])<=90)
            u++;
        else if(int(a[i])>=97&&int(a[i])<=122)
            l++;
    }
   // cout<<int(a[0])<<" "<<int(a[1])<<" "<<int(a[2])<<" ";
   // cout<<s<<" "<<d<<" "<<u<<" "<<l;
    int ans=0,di;
   if(6-n>0)
   {
       di=6-n;
   }
    if(s==0)ans++;
    if(d==0)ans++;
    if(u==0)ans++;
    if(l==0)ans++;
    
    int ad=di-ans;
    if(ad>0)
        ans+=ad;
    cout<<ans;
        
    return 0;
}