#include <bits/stdc++.h>

using namespace std;

int minimumNumber(int n, string str) {
    int f1,f2,f3,f4,count=0;
f1=f2=f3=f4=0;
    for(int i=0;i<n;i++)
    {if(str[i]>=65 && str[i]<=90)
        f1=1;
     else if(str[i]>=97 && str[i]<=122)
         f2=1;
     else if(str[i]>=48 && str[i]<=57)
         f3=1;
     else
         f4=1;}
   if(f1==0)
   {count++;n++;}
    if(f2==0)
    {count++;n++;}
    if(f3==0)
    {count++;n++;}
    if(f4==0)
    {count++;n++;}
    if(n<6)
        count=count+6-n;
    return count;
}

int main() {
    int n;
    cin >> n;
    string password;
    cin >> password;
    int answer = minimumNumber(n, password);
    cout << answer << endl;
    return 0;
}