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

int minimumNumber(int n, string s ) {
  string ns= "0123456789" ;
  string low =  "abcdefghijklmnopqrstuvwxyz" ;
  string up = "ABCDEFGHIJKLMNOPQRSTUVWXYZ" ;
  string spe = "!@#$%^&*()-+" ;
  unordered_set<char> a,b,c,d ;
  int u,v,w,x,y,z, r ;
  w = x = y = z = 0 ;
  r = 0 ;
  for( auto x : ns  ) a.insert( x  ) ;
  for( auto x : low ) b.insert( x  ) ;
  for( auto x : up ) c.insert( x  ) ;
  for( auto x : spe ) d.insert( x  ) ;
  for( auto l : s ){
    if( a.count(l) ) w ++ ;
    if( b.count(l) ) x ++ ;
    if( c.count(l) ) y ++ ;
    if( d.count(l) ) z ++ ;
  }
  if( !w ) r ++ ;
  if( !x ) r ++ ;
  if( !y ) r ++ ;
  if( !z ) r ++ ;
  if( n + r  < 6 )
    r += ( 6-r-n );
  return r ;
}

int main() {
    int n;
    cin >> n;
    string password;
    cin >> password;
    int answer = minimumNumber(n, password);
    cout << answer << endl;
    return 0;
}