#include<bits/stdc++.h>
using namespace std;
#define piii pair<int,pair<int,int> >
#define pii pair<int,int>
#define ll long long
string num="0123456789";
string lo="abcdefghijklmnopqrstuvwxyz";
string up="ABCDEFGHIJKLMNOPQRSTUVWXYZ";
string sp="!@#$%^&*()-+";
bool ch(string s,char c){
    for(int i=0;i<s.length();i++){
        if(s[i]==c){
            return 1;
        }
    }
    return 0;
}
int a[4];
int main()
{
    std::ios::sync_with_stdio(false); //I/O faster use'\n' in place of endl
    cin.tie(NULL);
    int n;
    cin>>n;
    string s;
    cin>>s;
    for(int i=0;i<s.length();i++){
       a[0]|=ch(num,s[i]);
        a[1]|=ch(lo,s[i]);
        a[2]|=ch(up,s[i]);
        a[3]|=ch(sp,s[i]);
    }

    int t=a[0]+a[1]+a[2]+a[3];
    //cout<<t;
    if(s.length()>=6){
        cout<<4-t;
    }
    else{
        cout<<max(6-((int)s.length()),4-t);
    }
    return 0;
}