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


int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
string numbers = "0123456789";
string lower_case = "abcdefghijklmnopqrstuvwxyz";
string  upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
string special_characters = "!@#$%^&*()-+";
string s;
    int n,i,u=0,l=0,nu=0,sp=0,x=0;
    cin>>n;
    cin>>s;
    for(i=0;i<n;i++)
    {
        if(lower_case.find(s[i])!=string::npos)
            u++;
        else if(upper_case.find(s[i])!=string::npos)
            l++;
        else if(numbers.find(s[i])!=string::npos)
            nu++;
        else if(special_characters.find(s[i])!=string::npos)
            sp++;
         
    }
    
    if(u>0 && l>0 && nu>0 && sp>0 && n>=6)
        cout<<0;
   else 
   {if(u==0)
        x++;
    if(l==0)
        x++;
    if(nu==0)
        x++;
    if(sp==0)
        x++;
    
    
    if(n+x>=6)
        cout<<x;
    else cout<<6-n;
   }
    return 0;
}