#include <iostream>

using namespace std;

int main() {
    int o;
    cin>>o;
    string s;
    cin>>s;
    int i,j,l,sum=0,f1=0,f2=0,f3=0,f4=0,f5=0,f6=0;
    l = s.size();
    for(i=0;i<l;i++)
    {
        j = s[i];
        if(j>=48&&j<=57)
        {
            if(f1==0)
            {
                sum++;
                f1=1;
            }
        }
        else if(j>=97&&j<=122)
        {
            if(f2==0)
            {
                sum++;
                f2=1;
            }
        }
        else if(j>=65&&j<=91)
        {
            if(f3==0)
            {
                sum++;
                f3=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]=='+')
        {
           if(f4==0)
           {
               sum++;
               f4=1;
           }
        }
    }
    if(l>=6)
    {
        cout<<4-sum;
    }
    else
    {
        j = 6-l;
        int r;
        r = 4-sum;
        if(j>=r)
            cout<<j;
        else
        {
            cout<<r;
        }
    }
}