#include <bits/stdc++.h>
using namespace std;
void fastscan(int  &number)
{
    bool negative = false;
    register int c;
    number = 0;
    c = getchar();
    if (c=='-')
    {
        negative = true;
        c = getchar();
    }
    for (; (c>47 && c<58); c=getchar())
        number = number *10 + c - 48;
    if (negative)
        number *= -1;
}

int main() {
	// your code goes here
	 ios_base::sync_with_stdio(false);
      cin.tie(NULL);
      int n;
      cin >> n;
      string s;
      cin >> s;
      bool uc=false,lc=false,dig=false,sp=false;
      for(int i=0; i<n; i++)
      {
           if(s[i]>='a' && s[i] <='z')
           {
                lc=true;
           }
           else if(s[i]>='A' && s[i] <='Z')
           {
                uc=true;
           }
           else if(s[i] >='0' && s[i] <='9')
           {
                dig=true;
           }
           else
           {
                sp=true;
           }
           
      }
    //  cout << uc << lc << dig << sp << endl;
      int count=0;
      if(!uc)
      {
           count++;
      }
      if(!lc)
      count++;
      if(!dig)
      count++;
      if(!sp)
      count++;
    //  cout << "ct: " << count << endl;
      if(n<6  && (6-count-n)>0)
      {
           count=count+(6-count-n);
      }
      
      cout << count << endl;
     
      
	return 0;
}