#include <bits/stdc++.h>

using namespace std;

int minimumNumber(int n, string p) {
    // Return the minimum number of characters to make the password strong
    bool c,l,no,s;
    c=l=no=s=false;
    int ans=0;
    for(int i=0;i<n;i++)
    {
        if((p[i]-'a'>=0)&&(p[i]-'a')<26)    c=true;
        if((p[i]-'A'>=0)&&(p[i]-'A')<26)    l=true;
        if((p[i]-'0'>=0)&&(p[i]-'0')<=9)    no=true;
        if((p[i]-'!'>=0)&&(p[i]-'!')<=12)    s=true;
    }
    if(!c)  ans++;
    if(!l)  ans++;
    if(!no) ans++;
    if(!s)  ans++;
    if(n+ans<6) return ans+(6-n-ans);
    else    return ans;
}

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