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

int main(){
    int n;
    cin>>n;
    string s;
    cin>>s;
    int count[4]={0};
    for(int i=0;i<n;i++){
        if((s[i]-'0')>=0 && (s[i]-'0')<=9){
            count[0]++;
        }
        else if((s[i]-'0')<=74 && (s[i]-'0')>=49){
            count[1]++;
        }
        else if((s[i]-'0')<=42 && (s[i]-'0')>=17){
            count[2]++;
        }
        else{
            count[3]++;
        }
    }
    int ans=0;
    for(int i=0;i<4;i++){
        if(count[i]<1){
            ans++;
        }
    }
    if(n+ans>=6){
        cout<<ans<<endl;
    }
    else{
        n=n+ans;
        cout<<(6-n+ans)<<endl;
    }
    return 0;
}