#include<bits/stdc++.h>
using namespace std;
int main() 
{
    int n;
    cin>>n;
    string str;
    cin>>str;
    
    int arr[4] = {0,0,0,0};
    
    for ( int i = 0 ; i < n ; i++)
    {
        if (str[i]>='0' && str[i]<='9') arr[0]=1;
        if (str[i]>='a' && str[i]<='z') arr[1]=1;
        if (str[i]>='A' && str[i]<='Z') arr[2]=1;
        if (str[i]=='!' || str[i]=='@' || str[i]=='#' || str[i]=='$' || str[i]=='%' || str[i]=='^' || str[i]=='&' || str[i]=='*' || str[i]=='(' || str[i]==')' || str[i]=='-' || str[i]=='+' ) arr[3]=1;
    }
 
    int res = 0;
    if(arr[0] == 0 ) res++;
    if(arr[1] == 0 ) res++;
    if(arr[2] == 0 ) res++;
    if(arr[3] == 0 ) res++;
    
    if ((n + res) >= 6) cout<<(res);
    else cout<<(6-n);
    
    
    return 0;
}