#include <bits/stdc++.h>

using namespace std;

int minimumNumber(int n, string password) {
    string h=password;
    int lo=0,hi=0,spe=0,num=0;
    
    int flag=0;
    // Return the minimum number of characters to make the password strong
    for(int i=0;i<h.length();i++){
    if((h[i]>='a')&&(h[i]<='z')&&(lo==0))
        lo=1;

else if((h[i]>='A')&&(h[i]<='Z')&&(hi==0))
hi=1;
else if((spe==0)&&((h[i]>=' ')&&(h[i]<='/'))||((h[i]>=':')&&(h[i]<='@'))||((h[i]>='[')&&(h[i]<='`'))||((h[i]>='{')&&(h[i]<='~')))
spe=1;
else if((num==0)&&(h[i]>='0')&&(h[i]<='9'))
num=1;
}
    int fl=0;
    if(num==0)
        fl++;
    if(hi==0)
        fl++;
    if(spe==0)
        fl++;
    if(lo==0)
        fl++;
    if((h.length()+fl)<6)
    {
        int l=6-(h.length()+fl);
        fl+=l;
    }
    return fl;
}

int main() {
    int n;
    cin >> n;
    string password;
    cin >> password;
    int answer = minimumNumber(n, password);
    cout << answer << endl;
    return 0;
}