#include <bits/stdc++.h>
#define ll long long int
using namespace  std;


int main(){
    ios::sync_with_stdio(0);
    cin.tie(0);
    
    int n;
    cin>>n;
    string s;
    cin>>s;
    bool dig  = false;
    bool lE = false;
    bool uE = false;
    bool sp = false;
    for (int i = 0; i<s.length(); i+=1) {
        if(s[i]>='0' and s[i]<='9')
        {
            dig = true;
        }
        else if (s[i]>='a' and s[i]<='z')
        {
            lE = true;
        }
        else if (s[i]>='A' and s[i]<='Z')
        {
            uE = true;
        }
        else{
            sp = true;
        }
    }
    int ans= 0 ;
    ans+=dig;
    ans+=lE;
    ans+=uE;
    ans+=sp;
    if(s.length()>=6)
    {
        cout<<4-ans<<endl;
    }
    else{
        int rem = 4-ans;
        if(s.length()+rem<6)
        {
            cout<<6-s.length();
        }
        else{
            cout<<rem<<endl;
        }
    }
    
    return 0;
}