#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;


int main() {
    int n;
    cin>>n;
    string s;
    cin>>s;
    int d,l,u,c;
    d=l=u=c=0;
    for(int i=0;i<n;i++){
        if(s[i]-'0'>=0 && s[i]-'0'<=9)
            d=1;
        else if(s[i]-'a'>=0 && s[i]-'a'<26)
            l=1;
        else if(s[i]-'A'>=0 && s[i]-'A'<26)
            u=1;
        else if(s[i]=='!' || s[i]=='@' || s[i]=='#' || s[i]=='$' || s[i]=='%' || s[i]=='^'|| s[i]=='&' || s[i]=='*' || s[i]=='('  || s[i]==')' || s[i]=='-' || s[i]=='+')
            c=1;
    }
    if(n+4-(d+l+c+u)<=6) cout<<6-n;
    else cout<<4-(d+l+c+u);
    return 0;
}