#include<bits/stdc++.h>
using namespace std;
int main()
{
    int n, i;cin>>n;
    int a[4]={0};
    int cnt=0;
    string s;
    cin>>s;
    for(i=0;i<n;i++)
    {
      if(s[i]>=97 && s[i]<=122)
          a[0]=1;
        if(s[i]<=90 && s[i]>=65) a[1]=1;
        if(s[i]>=48 && s[i]<=57) a[3]=1;
        if(s[i]=='!' || s[i]=='@' || s[i] =='#' || s[i]=='$'  || s[i]=='%' || s[i]=='^' || s[i]=='&' || s[i]=='*' || s[i]=='(' || s[i]==')' || s[i]=='-' || s[i]=='+' ) a[2]=1;  
       
    }
    int ans;
    for(i=0;i<4;i++)
    {if(a[i]==1) cnt++;}
    if(n>6)
    { 
    
        ans=4-cnt;
        cout<<ans;
        return 0;
    }
    else
    {
       cnt=4-cnt;
        n=6-n;
        ans=max(cnt,n) ;
            cout<<ans;
    }
}