#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 cont = 0;
    if(n < 6)
    {
        cont = 6 - n; 
    }
    int num = 0, lower = 0, upper = 0, special = 0; 
    for(long long int i = 0 ; i< n ; i++)
    {  
        if( password[i]  >= '0' && password[i] <= '9' )
            num  = 1;
        if( password[i]  >= 'a' && password[i] <= 'z' )
            lower  =1;
        if( password[i]  >= 'A' && password[i] <= 'Z' )
            upper  =1;
        if( password[i]  >= 33 && password[i] <= 45 )
            special  =1;
        
    }
    int count = 0;
    if(num == 0)
    {
        count++;
    }
    if(special == 0)
    {
        count++;
    }
     if(lower == 0)
    {
        count++;
    }
     if(upper == 0)
    {
        count++;
    }
    return max(count, cont);
}

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