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


int main() {
    int n,U=0,L=0,S=0,N=0,count=4,extra;
    cin>>n;
    string s;
    cin>>s;
    for(int i=0;i<n;i++)
    {
        if(int(s[i])>=65 && int(s[i])<=90)
            U++;
        else if(int(s[i])>= 97&& int(s[i])<=122)
            L++;
        else if (int(s[i])>=48 && int(s[i])<=57)
            N++;
        else S++;
    }
    //cout<<N<<endl<<U<<endl<<L<<endl<<S<<endl;
        if(U>0)
            count--;
        if(L>0)
            count--;
        if(N>0)
            count--;
        if(S>0)
            count--;
    
    extra=6-n;
    if(extra>count)
        cout<<extra;
    else
    cout<<count<<endl;
    
    
}