#include<bits/stdc++.h>
using namespace std;


int main() {
    string numbers = "0123456789";
 string lower_case = "abcdefghijklmnopqrstuvwxyz";
string upper_case = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
string special_characters = "!@#$%^&*()-+";
    int n;
    string s;
    cin>>n;
    cin>>s;
    int countn=0,countl=0,countu=0,counts=0,count=0;
    for(int i=0;i<n;i++)
    {
        if(numbers.find(s[i])!=string::npos)
            countn=1;
        if(lower_case.find(s[i])!=string::npos)
            countl=1;
        if(upper_case.find(s[i])!=string::npos)
            countu=1;
        if(special_characters.find(s[i])!=string::npos)
            counts=1;
        
    }
    count=countn+countl+countu+counts;
    if(n>5)
        cout<<4-count;
    else
    {
        int extra=6-n;
        cout<<max(extra,4-count);
    }
    
    return 0;
}