#include <bits/stdc++.h>
using namespace std;
#define REP(i,a,b) for(int i=a;i<b;i++)
#define NREP(i,a,b) for(int i=a;i>=b;i--)
#define CLR(a,t) memset(a,t,sizeof a)
#define help ios::sync_with_stdio(0)
#define TCASE int t;cin>>t;while(t--)
#define f first
#define s second
#define mp make_pair
#define pb push_back

int main(){
    help;
    int n;
    string str;
    int up=0,low=0,dig=0,ans=0,ans2=0,spe=0;
    cin>>n>>str;
    if(n<6) ans=6-n;
    REP(i,0,n){
        if(str[i]>='0' and str[i]<='9') dig=1;
        else if(str[i]>='a' and str[i]<='z')    low=1;
        else if(str[i]>='A' and str[i]<='Z')    up=1;
        else if(str[i]=='!' or str[i]=='@' or str[i]=='#' or str[i]=='$' or str[i]=='%' or str[i]== '^' or str[i]=='&' or str[i]=='*' or str[i]=='(' or str[i]==')' or str[i]=='-' or str[i]=='+')
            spe=1;
    }
    ans2=4-(dig+low+up+spe);
    cout<<max(ans2,ans)<<endl;
    return 0;
}