#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define ull  unsigned long long
#define ld long double
#define endl '\n'
#define pb push_back
#define mp make_pair
#define ft first
#define sc second
#define y1 ngngwengngigwi
#define x1 wejfiegnepgn
#define files freopen("input.txt","r",stdin);freopen("output.txt","w",stdout);
#define filesin(x) freopen(x".in","r",stdin);freopen(x".out","w",stdout);
#define filestxt(x) freopen(x".txt","r",stdin);//freopen(x".txt","w",stdout);
#define iosbase ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define toch(x) fixed<<setprecision(x)
#define all(x) x.begin(),x.end()
#define pii pair < int , int >
#define pll pair < ll , ll >
#define sqr(x) ((x)*(x))

const ll inf=2e9;
const ll md=1e9+7;
const ll  P=27;
const ld ex=0.000000001;
const ld pi=3.14159265358979323846;

string s;
int q,fa,fA,f1,n,fsp;

int main()
{
    iosbase;
    //files;
    cin>>n;
    cin>>s;
    for(int i=0;i<n;i++)
    {
        if(s[i]>='A' && s[i]<='Z')fA=1;
        if(s[i]>='a' && s[i]<='z')fa=1;
        if(s[i]>='0' && s[i]<='9')f1=1;
        if(s[i]=='#')fsp=1;
        if(s[i]=='!')fsp=1;
        if(s[i]=='@')fsp=1;
        if(s[i]=='$')fsp=1;
        if(s[i]=='%')fsp=1;
        if(s[i]=='^')fsp=1;
        if(s[i]=='&')fsp=1;
        if(s[i]=='*')fsp=1;
        if(s[i]=='(')fsp=1;
        if(s[i]==')')fsp=1;
        if(s[i]=='-')fsp=1;
        if(s[i]=='+')fsp=1;
    }
    q=(1-fA)+(1-fa)+(1-f1)+(1-fsp);
    cout<<max(q,6-n);
}
///DO0122