#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;
int main() {
    int n,i;
    char c;
    bool b1=0,b2=0,b3=0,b4=0;
    cin>>n;
    for(i=0;i<n;i++)
    {
        cin>>c;
        if(48<=c&&c<58)
            b1=1;
        else if(65<=c&&c<=90)
            b2=1;
        else if(97<=c&&c<=122)
            b3=1;
        else
            b4=1;
    }
    i=4-b1-b2-b3-b4;
    if(n+i>=6)
        cout<<i;
    else
        cout<<6-n;
    return 0;
}