#include <bits/stdc++.h>

using namespace std;

int main() {
    int n,i;
    cin >> n;
    string s;
    cin >> s;
    //int answer = minimumNumber(n, password);
    int ct[4]={0,0,0,0};
    for(i=0;i<n;i++){
        if(s[i]<='Z'&&s[i]>='A')
            ct[0]++;
        else if(s[i]<='z'&&s[i]>='a')
            ct[1]++;
        else if(s[i]<='9'&&s[i]>='0')
            ct[2]++;
        else 
            ct[3]++;
    }
    int ct1=0;
    for(i=0;i<4;i++){
        if(!ct[i])
            ct1++;
    }
    if(ct1+n<6)
    {
        ct1= 6-n;
    }
    cout << ct1 << endl;
    return 0;
}