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


int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    
    int n;
    char arr[100];
    cin>>n;
    
    cin>>arr;
    
    int cl,cu,cd,cs;
    
    cl=cu=cd=cs=0;
    
    int count;
    
    for(int i=0;i<n;i++)
    {
        if(arr[i]>='0' && arr[i]<='9')
            cd++;
        else if(arr[i]>='a' && arr[i]<='z')
            cl++;
        else if(arr[i]>='A' && arr[i]<='Z')
            cu++;
        else cs++;
    }
    
    if(cl==0)
    {
        cl++;
        count++;
    }
    
    
    if(cu==0)
    {
        cu++;
        count++;
    }
    
    if(cs==0)
    {
        cs++;
        count++;
    }
    
    
    if(cd==0)
    {
        cd++;
        count++;
    }
    
    if(cs+cd+cu+cl >= 6)
    {
        cout<<count;
    }else {
        
        cout<<count + 6 - (cs+cd+cu+cl);
    }
    
    
    
    return 0;
}