// avvinci - sem_7 
// #include"prettyprint.hpp"
#include<bits/stdc++.h>
using namespace std;

typedef pair<long long int , long long int> P;

#define mod 1000000007 
#define pb push_back
#define mk make_pair
#define fs first
#define sc second
#define ll long long int
#define fr(it,st,en) for(it=st;it<en;it++)
#define all(container) container.begin(),container.end()
#define INP ios_base::sync_with_stdio(false);cin.tie(NULL);
#define ws(x) cout << #x << " = " << x << endl
#define sz(x)  (ll)x.size()
#define N 1000004

const long long infl = 1e18+5;

ll n,m,k,q,x,y,f,val,t=1,i,j;
ll ind = -1,cnt,sz,sm,ans,mx = -1,mn = infl ;
ll a[N] ;

int main(){
INP

cin>>n;
m = n ;
ll x = 1 , y = 1, z = 1, w = 1 ; 
string s ;
 cin>>s ;
  fr(i,0,n){
    if( s[i] >= 'a' && s[i] <= 'z') x =0 ; 
    else if(s[i] >= 'A' && s[i] <= 'Z') y = 0 ;
    else if(s[i] >= '0' && s[i] <= '9') z = 0 ;
    else w = 0 ; 
   }
   n += x+y+z+w ; 
   n = max(n,6LL) ; 
   cout<<n - m ; 



return 0 ;
}