#include <iostream> 
#include <sstream>
#include <cstdio>
#include <cmath>
#include <cstring>
#include <cctype>
#include <string>
#include <vector>
#include <unordered_set>
#include <set>
#include <iomanip>
#include <unordered_map>
#include <map>
#include <queue>
#include <stack>
#include <algorithm>
#include <functional>
using namespace std;
#define F first
#define S second
#define EB emplace_back
#define MP make_pair
#define all(o) (o).begin(), (o).end()
#define mset(m,v) memset(m,v,sizeof(m))
#define fr(i,n) for(lli i=0;i<n;++i)
#define rep(i,a,b) for(lli i=a;i<=b;++i)
#define per(i,b,a) for(lli i=b;i>=a;--i)
#define remin(a,b) (a=min((a),(b)))
#define remax(a,b) (a=max((a),(b)))
#define chartostr(x) string(1,(char)(x))
#define fastIO ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0)
typedef long int li;          typedef long long int lli;
typedef long double ld;       typedef pair< lli,lli > ii;
template <class T> inline T binpow(T p,T e,T M){lli ret = 1;for(; e > 0; e >>= 1){if(e & 1) ret = (ret * p) % M;p = (p * p) % M;}return (T)ret;}
template <class T> inline T gcd(T a,T b){if(b==0)return a;return gcd(b,a%b);}
template <class T> inline T modinverse(T a,T M){return bigmod(a,M-2,M);}   // M is prime} 
typedef vector<lli> vi;       typedef vector<ii> vii;
typedef vector<vi> graph;     lli MOD=1000000007;long double EPS=1e-9;
lli countbits(lli n){lli count=0;while(n){n = n&(n-1);count++;}return count;}
lli tolli(string s){lli sm;stringstream ss(s);ss>>sm;return sm;}
vi tobinary(lli n){vi bin;while(n){bin.EB(n%2);n/=2;};reverse(all(bin));return bin;}




void pre(){

}

void solve(){
	int n;
	cin>>n;
	string a;
	cin>>a;
	int arr[4];
	mset(arr,0);
	for(int i=0;i<a.length();i++){
		if(	a[i]<='9'&&a[i]>='0')arr[0]++;
		else if(a[i]<='z'&&a[i]>='a')arr[1]++;
		else if(a[i]<='Z'&&a[i]>='A')arr[2]++;
		else arr[3]++;
	}	
	lli ans=4;
	if(arr[0])ans--;
	if(arr[1])ans--;
	if(arr[2])ans--;
	if(arr[3])ans--;
	if(a.length()<6)ans=max((lli)(6-a.length()),ans);
	cout<<ans;

}

int main(){
	fastIO;
	pre();
	int t=1;
	//cin>>t;
	for(int i=1;i<=t;i++){
		solve();
	}
}