#include <bits/stdc++.h>

using namespace std;

int minimumNumber(int n, string password) {
    // Return the minimum number of characters to make the password strong
    int l = 0,u=0,num=0,s=0,count=0;
    int m = password.length();
    for(int i =0;i<m;i++)
    {
        if(password.at(i)>=65&&password.at(i)<=90)
            u++;
        if(password.at(i)>=97  &&password.at(i)<=122)
            l++;
        if(password.at(i)>='0'&&password.at(i)<='9')
            num++;
        if(password.at(i)>=33&&password.at(i)<=45)
            s++;}
        if(l==0) count++;
        if(u==0) count++;
        if(num==0) count++;
        if(s==0) count++;
        
        if(m+count>=6)
            return count;
        else
            return (6-m);
    
}

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