#include<bits/stdc++.h>
using namespace std;
#define f(i,n) for(long long i=0;i<n;i++)
#define ll long long
#define F first
#define S second
long long bin(vector< pair< long long,long long > > a,long long l,long long r,long long x){
	while(l<r){
		long long mid=l+ (r-l)/2;
		if(x<a[mid].second){
			r=mid-1;
		}
		else if(x>a[mid].second)
		l=mid+1;
		else if(x==a[mid].second)
		return mid;
	}
	return l;
}
long long x,y;
long long exp(long long  x,long long  y,long long m ){
	if(y==0)
	return 1;
	else if( y % 2 == 0 )
	return (exp(((x%m)*(x%m))%m,y/2,m))%m;
	else
	return ((x%m)*exp(((x%m)*(x%m))%m,(y-1)/2,m))%m;
}

long long d;
void extendedEuclid(long long A, long long B) {
    if(B == 0) {
        d = A;
        x = 1;
        y = 0;
    }
    else {
        extendedEuclid(B, A%B);
        long long temp = x;
        x = y;
        y = temp - (A/B)*y;
    }
}

long long modInverse(long long A, long long M)
{
    extendedEuclid(A,M);
    return (x%M+M)%M;    //x may be negative
}
set<long long> se;	
vector<bool>  seive(int a){
	int c=0;
vector<bool> v(a+1);
	//memset(v,false,sizeof(v));
f(i,a+1)
v[i]=false;
	v[0]=v[1]=true;
	for(int i=2;i*i<=a;i++){
		if(v[i]==false)
		for(int j=i*i;j<=a;j+=i)
		v[j]=true;
	}
return v;
f(i,a+1)
if(v[i]==false)
se.insert(i);
}

int main(){
	ll n,m,k,a,d;
	pair<ll,ll> p;
    string s;
ll ans=0;
    string nu = "0123456789";
string lc = "abcdefghijklmnopqrstuvwxyz";
string uc = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
string sc = "!@#$%^&*()-+";
	cin>>n;
	cin>>s;
	
	ans=4;
	f(i,n){
		if(nu.find(s[i])!=-1){
		ans--;
		break;	
}
		}
f(i,n){
		if(lc.find(s[i])!=-1){
		ans--;
		break;	
	}	}

f(i,n){
		if(uc.find(s[i])!=-1){
		ans--;
		break;	
		}
	}

f(i,n){
		if(sc.find(s[i])!=-1){
		ans--;
		break;	
		}
		}
	if(n>=6)
		cout<<ans;
		else 
		cout<<max(ans,6-n);
		
	//vector< pair < ll,ll > > vp(n);

return 0;	
	}