#include<bits/stdc++.h>
using namespace std;
/**************************SHORTCUTS**********************/
#define nl cout<<'\n';
#define endl '\n'
#define its iterator
#define faster ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define ff first
#define ss second
#define pb push_back
#define pf push_front
#define mp make_pair
#define rep(i,n) for(int i=0;i<n;i++)
#define rep1(i,a,n) for(int i=a;i<n;i++)
#define TEST int testow;cin>>testow;while(testow--)
/**************************END OF SHORTCUTS**************/
/**************************MATH STUFF********************/
#define mod 1000000007
#define Pi 3.141592653589793
#define gcd(a,b)  __gcd(a,b)
/**************************END OF MATH STUFF************/
/**************************TO USE DEBUGGING**************/
//#define online
/***************************END OF DEBUGS****************/
 
 
 
/***************************OFFLINE USE ONLY************/
#ifndef online
#define deb(x) cout<<#x<<" "<<x<<endl;
#define deb2(x,y) deb(x);deb(y)nl;
#define deb3(x,y,z) deb(x);deb(y);deb(z)nl;
#define openup freopen("input.txt","r",stdin);
#define track cout<<"control has reached to line : "<<__LINE__<<endl;
void delay(unsigned int mseconds){clock_t goal = mseconds + clock();    while (goal > clock());}
#endif // online
/***************************END OF OFFLINE USE****************/
/***************************FAKE*****************************/
#ifdef online
#define deb(x)
#define deb2(x,y)
#define deb3(x,y,z)
#define openup
#define track
void delay(unsigned int x){}
#endif // online
/***************************END OF FAKE*********************/
/***************************STL*****************************/
typedef unsigned long long ull;
typedef long long ll;
typedef pair<ll,ll> pll;
typedef pair<int,int> pii;
typedef vector<ll> vll;
typedef vector<int> vi;
#define all(x) (x).begin(),(x).end()
#define REV(a) reverse(all(a))
#define remax(a,b) a=max(a,b);
#define remin(a,b) a=min(a,b);
/**************************END OF STL**********************/
 
/**************************CODE STARTS HERE****************/
int main()
{
  faster;
  string s;
    int n;
    cin>>n;
  cin>>s;
  string special="!@#$%^&*()-+";
  int ans[4]={0};
  rep(i,s.size())
  {
      if(s[i]<='9'&&s[i]>='0')
      {
          //cout<<i<<endl;
          ans[0]=true;
      }
      if(islower(s[i]))
      ans[1]=true;
      if(isupper(s[i]))
      ans[2]=true;
      for(int j=0;j<special.size();j++)
      {
          if(s[i]==special[j])
          {
             ans[3]=true;
              break;
          }
      }
  }
    //deb(ans[0]);
   // deb3(ans[1],ans[2],ans[3])
  if(s.size()>=6)
  cout<<4-ans[1]-ans[2]-ans[3]-ans[0]<<endl;
  else
      cout<<max(4-ans[1]-ans[2]-ans[3]-ans[0],6-(int)s.size())<<endl;
   return 0;
}